How to manufacture adjustable midsoles for footwear products

Abstract

To provide a midsole which reduces kinetic energy and resulting momentum from a user's foot strike, so as to enable athletic activities with less fatigue.SOLUTION: A method of making a midsole comprises the steps of: selecting a plurality of yarns, where at least two yarns of the plurality of yarns have properties different from one another; bundling the plurality of yarns to form a bundled yarn structure; intertwining the yarn structure; depositing the twisted yarn structure in a first mold within an autoclave; applying supercritical fluid to the twisted yarn structure; infiltrating and saturating the twisted yarn structure with the supercritical fluid; depressurizing the autoclave to cause a foaming process to convert the twisted yarn structure into an anisotropic foam blank; and depositing the anisotropic foam blank within a second mold that is configured as a midsole for an article of footwear.SELECTED DRAWING: Figure 16

Description

Technical Field

[0001] [Cross - Reference to Related Applications] This application claims the benefit and priority of U.S. Provisional Application No. 63 / 388,523, filed on July 12, 2022, which is hereby incorporated by reference in its entirety.

Background Art

[0002] Field of the Disclosure The present invention generally relates to articles of footwear including anisotropic foams made from various pre - oriented yarn structures ).

[0003] Many conventional shoes or other articles of footwear generally include an upper and a sole attached to the lower end of the upper. Conventional shoes further include an internal space for receiving the user's foot before the shoe is secured to the foot, i.e., a void or cavity formed by the inner surfaces of the upper and the sole. The sole is attached to the lower surface or boundary of the upper and is disposed between the upper and the ground. As a result, the shoe sole typically provides stability and cushioning to the user when the shoe is being worn. In some examples, the sole can include multiple components such as an outsole, a midsole, and an insole. The outsole may provide static friction to the bottom surface of the sole, and the midsole may be attached to the inner surface of the outsole. The sole may also include additional components such as plates embedded in the sole to increase the overall rigidity of the sole and reduce energy loss during use.

[0004] The upper generally extends upward from the sole, defining an internal cavity that completely or partially encloses the foot. In most cases, the upper extends across the instep and toe areas of the foot, as well as across its inner and outer sides. Many footwear products may also include a tongue that bridges the gap between the inner and outer ends of the upper, extending across the instep area and defining an opening into the cavity. The tongue may also be located below the lacing system and between the inner and outer sides of the upper to allow for adjustment of the shoe's tightness. The tongue may be further manipulated by the user to allow the foot to enter or exit the internal space or cavity. In addition, the lacing system may allow the user to adjust specific dimensions of the upper or sole, thereby enabling the upper to accommodate a wide variety of foot shapes with varying sizes and shapes.

[0005] The upper may comprise a wide variety of materials that can be selected based on one or more intended uses of the shoe. The upper may also comprise sections containing various materials specific to certain areas of the upper. For example, stability can be added near the forefoot or heel of the upper by providing greater resistance or rigidity. In contrast, other parts of the shoe may comprise soft woven fabrics to provide areas that are stretch-resistant, flexible, breathable, or moisture-wicking.

[0006] The sole assembly generally extends between the ground and the upper. In some embodiments, the sole assembly includes an outsole that provides abrasion resistance and static friction with the ground, and a multi-component midsole that provides lever-like support and toe stabilization. The multi-component midsole includes a lower midsole cushioning member, an upper midsole cushioning member, and a plate positioned between the upper and lower cushioning members. The plate, usually formed from carbon fiber or other composite material, absorbs the kinetic energy and resulting momentum from the impact of the user's foot. This helps users perform less tiring exercise activities.

[0007] Many shoes currently available possess various features related to the characteristics mentioned above, but many shoes, more specifically their midsoles, can be further optimized. [Overview of the Initiative]

[0008] In some embodiments, the manufacturing method of the midsole involves a step of selecting multiple yarns. The method includes a step of bundling the yarns together to form a bundled yarn structure, and a step of intertwining the bundled yarn structure to form a twisted yarn structure. The intertwining step involves fixing the ends of the bundled yarn structure, applying axial tension to the bundled yarn structure, and rotating the bundled yarn structure. The method includes the step of forming a twisted yarn structure. Furthermore, the method includes the step of depositing the twisted yarn structure into a first mold in an autoclave, and This includes applying a supercritical fluid to the twisted yarn structure. Furthermore, the method includes the steps of applying a supercritical fluid to the twisted yarn structure to infiltrate and saturate the twisted yarn structure with the supercritical fluid, and converting the twisted yarn structure into an anisotropic foam blank. To initiate the foaming process, the autoclave is depressurized. ) and the process of making the anisotropic foam blank into an article of footwear This includes the process of depositing the material into a second mold that is configured as the midsole.

[0009] In some embodiments, at least one of the plurality of threads is made of a thermoplastic polymer, a thermosetting polymer, or an elastomer polymer. It consists of at least one of the following. In some embodiments, the anisotropic foam blank has a first cell growth direction parallel to the longitudinal direction of the twisted structure. Includes. In some embodiments, the anisotropic foam blank includes a second cell growth direction perpendicular to the longitudinal direction of the twisted structure. In some embodiments, the supercritical fluid includes superheated water, supercritical carbon dioxide, or both. In some embodiments, at least one of the plurality of yarns The diameter of one of the threads increases by at least 120%. In some embodiments, the density of at least one of the threads increases by at least 50%. It decreases.

[0010] In some embodiments, a method for manufacturing a midsole includes a step of selecting a plurality of yarns, wherein at least two of the plurality of yarns have different properties from each other. The method includes a step of bundling the plurality of yarns to form a bundled yarn structure, and a step of twisting the bundled yarn structure using a braiding technique to form a braided yarn structure. An axial tension is applied to the bundled yarn structure. Furthermore, the method includes a step of depositing the braided yarn structure in a first mold in an autoclave, and a step of applying a supercritical fluid to the braided yarn structure. The method also includes a step of impregnating and saturating the braided yarn structure with the supercritical fluid, a step of reducing the pressure in the autoclave to induce a foaming step to convert the braided yarn structure into an anisotropic foam blank, and a step of depositing the anisotropic foam blank in a second mold configured as a midsole for a footwear product.

[0011] In some embodiments, at least one of the plurality of threads is composed of at least one of a thermoplastic polymer, a thermosetting polymer, or an elastomer polymer. In some embodiments, the supercritical fluid is superheated water or supercritical carbon dioxide. or both. In some embodiments, the diameter of at least one of the plurality of threads is increased by at least 120%. In some embodiments, the density of at least one of the plurality of threads is decreased by at least 50%. In some embodiments, the circumferential shear strain of the plurality of threads is greater than 0.05. In some embodiments, the braiding technique is a braiding technique.

[0012] In some embodiments, the tunable midsole described herein is manufactured The method includes utilizing anisotropic foam. The anisotropic foam blank is placed between or within the segments of the midsole. Used as a replacement for a multi-component midsole structure, for example, to replace the existing midsole. It may be used. The anisotropic foam blank can be formed by twisting together multiple threads in a pre-oriented manner. The anisotropic foam blank is adjustable and pre-oriented to provide cushioning, stability, and It provides customized local characteristics such as energy dissipation or absorption, puncture resistance, and propulsion. It is a functional foam. Furthermore, the anisotropic foam material of this disclosure reduces the need to assemble or install multiple components, thereby reducing waste associated with excess material and minimizing the labor and energy consumption associated with assembling such structures.

[0013] In some embodiments, the midsole containing an anisotropic foam material may define the forefoot region, midfoot region, and heel region of the midsole. The anisotropic foam material includes an intertwined yarn structure containing multiple threads. The intertwined yarn structure may be a non-woven structure, a woven structure, a knitted structure, or a knitted structure. It can be formed as a braided structure or a twisted structure.

[0014] In some embodiments, the plurality of threads include the polymeric core. The polymeric core includes a first material. The first material may be a thermoplastic polymer, a thermosetting polymer, or an elastomer polymer. In some embodiments, the thickness, denier, and tear strength of the polymeric core are: It differs based on the material of the polymer core.

[0015] In some embodiments, the core material includes a second polymer material, the second polymer material being different from the first polymer material. The core material may include multiple materials, or different cores may include different materials. The number of cores varies based on the intertwined filament structure.

[0016] In some embodiments, a solvent or blowing agent is used to form the entangled thread structure The material is impregnated to form a multicellular foam, where the orientation of the cell growth direction provides anisotropic properties to the foam. The foam may include unidirectional cell growth, bidirectional cell growth, and radial cell growth. The cell growth direction, incorporated into the various intertwines of the body, provides a unique anisotropy.

[0017] In some embodiments, the intertwined structure and super A supercritical solvent is subjected to a pressurized autoclave, and the molecules of the supercritical solvent rapidly convert into a gas, forming multiple polyhedral cells within the material of the thread structure, and the orientation of the cell growth direction differs from that of the thread structure. It provides polarity. The solvent is a supercritical fluid such as carbon dioxide or nitrogen, or water. It may be a superheated fluid. The intertwined thread structure can be exposed to both supercritical fluids and superheated fluids to form an anisotropic foam. As a result of the foaming process, the diameter of the thread can increase by at least more than 10%. Depending on the material and the solvent, the diameter of the foam can show a large increase. In some embodiments, the anisotropic foam is compressed to undergo a second molding process to give the midsole a specific shape. The anisotropic foam is pre-oriented before the second molding process to provide different functionalities without including components within the midsole such as an upper midsole, a lower midsole, and a plate.

[0018] In some embodiments, the foaming process of the thread structure includes the selection of the thread material and the characteristics of the thread including, but not limited to, diameter, denier, tear strength, and color. The thread structure is formed after twisting the selected threads in a special way and pre-oriented within a mold. The mold is placed in an autoclave that softens the thread structure and allows the blowing agent to penetrate. The blowing agent induces cell growth in a specific direction during cell nucleation and is rapidly depressurized to produce the anisotropic foam. The foam undergoes a second compression molding step to give the midsole its specific shape. The anisotropic foam can be pre-oriented before the second molding process to provide different functionalities without including components within the midsole such as an upper midsole, a lower midsole, and a plate. In some embodiments, the foaming process of the thread structure includes the selection of the thread material and the characteristics of the thread including, but not limited to, diameter, denier, tear strength, and color. The thread structure is formed after twisting the selected threads in a special way and pre-oriented within a mold. The mold is placed in an autoclave that softens the thread structure and allows the blowing agent to penetrate. The blowing agent induces cell growth in a specific direction during cell nucleation and is rapidly depressurized to produce the anisotropic foam. The foam undergoes a second compression molding step to give the midsole its specific shape.

[0019] In some embodiments, the thread structure is formed by twisting the threads with controlled tension and twist angle. The control of the tension is provided by a small weight, and the twist angle can be controlled by the pitch of the rotation. In some embodiments, the thread structure is formed by twisting the threads with controlled tension and twist angle. The control of the tension is provided by a small weight, and the twist angle can be controlled by the pitch of the rotation.

[0020] In some embodiments, the thread structure is formed by twisting the threads with controlled tension and twist angle. The control of the tension is provided by a small weight, and the twist angle can be controlled by the pitch of the rotation.

[0021] In some embodiments, the thread structure is made using a Kumihimo disk. It is formed by braiding threads. The braiding machine controls the tension. The tension is provided by a small weight at the end of the bobbin.

[0022] In some embodiments, the yarn structure is pre-oriented within a mold. The mold defines the forefoot, midfoot, and heel regions of the midsole. The mold contains different yarn structures depending on the region, so that different yarn structures provide desired different functionalities, cushioning, and benefits to the particular region. Various types of yarn structures can be stacked, bundled, and / or sandwiched to achieve desired properties and functionalities.

[0023] In some embodiments, the second compression molding of the anisotropic foam including the filament structure is performed according to the ambient parameter of the foam. or the foaming of the yarn is at least 40 degrees above the operating parameter. Alternatively, it is done after foaming.

[0024] In some embodiments, the footwear product includes an upper and a midsole having a forefoot region, a heel region, and a midfoot region. The midsole includes a pre-oriented anisotropic foam in at least one of the forefoot region, the heel region, or the midfoot region.

[0025] In some embodiments, the pre-orientation anisotropic foam comprises a forefoot segment, a heel segment, and a midfoot segment. It is supplied in the form of separate segments including the above. In some embodiments, the midsole is a unitary structure having the pre-orientation anisotropic foam in the forefoot region, the heel region, and the midfoot region, respectively. In some embodiments, the The midsole has at least one difference between flexibility and rigidity between the forefoot region, the heel region, and the midfoot region. In some embodiments, the midsole comprises a plate in contact with the pre-orientation anisotropic foam. In some embodiments, the pre-orientation anisotropic foam is formed by at least one of a braided yarn structure or a twisted yarn structure.

[0026] Other embodiments of the method for manufacturing the adjustable midsole foam described herein, including processes, characteristics, and advantages thereof, will become apparent to those skilled in the art by examining the figures and the detailed description herein. Thus, all such embodiments of the process for manufacturing the adjustable midsole foam are intended to be included in the detailed description and this summary. [Brief explanation of the drawing]

[0027] [Figure 1] Figure 1 is a cross-sectional view of a polymer yarn containing a single core. [Figure 2] Figure 2 shows another cross-sectional view of multiple polymer yarns containing a single core with various characteristics. [Figure 3] Figure 3 is a diagram of the foamed structure. [Figure 4] Figure 4 shows a manufacturing system for mono-yarn strands using an extrusion process. [Figure 5] Figure 5 is a schematic diagram of the nonwoven yarn manufacturing process. [Figure 6]FIG. 6A is a perspective view of a portion of a bundle of yarn in an untwisted configuration, FIG. 6B is a perspective view of a bundle of yarn in a twisted configuration, and FIG. 6C is a magnified view of a portion of a bundle of yarn in a helical twist configuration. [Figure 7A] Figure 7A shows the first step in a sequence for producing twisted yarn with controlled pitch and tension. [Figure 7B] Figure 7B shows the second step in a sequence for producing twisted yarn with controlled pitch and tension. [Figure 7C] Figure 7C shows the third step in a sequence for producing twisted yarn with controlled pitch and tension. [Figure 7D] Figure 7D shows the fourth step in the sequence for producing twisted yarn, with controlled pitch and tension. [Figure 7E] Figure 7E shows the fifth step in the sequence for producing twisted yarn, with controlled pitch and tension. [Figure 8A] Figure 8A is a top plan view of the knitted yarn structure. [Figure 8B] Figure 8B is a top plan view of another knitted yarn structure. [Figure 8C] Figure 8C is a top plan view of yet another knitted yarn structure. [Figure 8D] Figure 8D is a top plan view of yet another knitted yarn structure. [Figure 8E] Figure 8E is a top plan view of another knitted yarn structure. [Figure 8F] Figure 8F is a top plan view of yet another knitted structure. [Figure 8G] Figure 8G is a top plan view of yet another knitted structure. [Figure 9] Figure 9 is a top plan view of the woven yarn structure. [Figure 10]FIG. 10A is a top view of the knitted yarn before foaming, FIG. 10B is a magnified top view of the knitted yarn before foaming, and FIG. 10C is a top view of the knitted yarn after foaming. [Figure 11A] Figure 11A shows the first step in the Kumihimo braiding sequence. [Figure 11B] Figure 11B shows the second step in the braiding sequence. [Figure 11C] Figure 11C shows the third step in the braiding sequence. [Figure 11D] Figure 11D shows the fourth step in the braiding sequence. [Figure 11E] Figure 11E shows the fifth step in the braiding sequence. [Figure 11F] Figure 11F shows the sixth step in the braiding sequence. [Figure 12A] Figure 12A is a top plan view of a knot. [Figure 12B] Figure 12B is a top plan view of another knot. [Figure 12C] Figure 12C is a top plan view of yet another knot. [Figure 12D] Figure 12D is a top plan view of yet another knot. [Figure 13] Figure 13 shows the principle process for manufacturing anisotropic foam from polymer yarn. [Figure 14] Figure 14 is a cross-sectional view of the polymer yarn shown in Figure 1 in a foamed state. [Figure 15A] Figure 15A is a perspective view of a cobra knot structure formed from polyamide 6 filaments before the foaming process. [Figure 15B] Figure 15B is a perspective view of a cobra knot structure formed from polyamide 6 filaments after the foaming process. [Figure 16] Figure 16 is a flowchart illustrating an example of the foaming process for a yarn structure. [Figure 17] Figure 17 is a perspective view of a high-pressure reactor. [Figure 18A] Figure 18A is a perspective view of the knitted yarn structure. [Figure 18B] Figure 18B is a perspective view of a foamed braided yarn structure. [Figure 19A] Figure 19A is a perspective view of a knitted yarn structure foamed at 108°C. [Figure 19B] Figure 19B is a perspective view of a knitted yarn structure foamed at 109°C. [Figure 19C] Figure 19C is a perspective view of a knitted yarn structure foamed at 110°C. [Figure 19D] Figure 19D is a perspective view of a knitted yarn structure foamed at 112°C. [Figure 20A] Figure 20A is a perspective view of the twisted yarn structure. [Figure 20B] Figure 20B is a perspective view of a foamed twisted yarn structure. [Figure 21A] Figure 21A is a perspective view of a twisted yarn structure immersed at 103°C and foamed at 34.5 MPa and 110°C. [Figure 21B] Figure 21B is a perspective view of a twisted yarn structure immersed at 102°C and foamed at 34.5 MPa and 108°C. [Figure 21C] Figure 21C is a perspective view of a twisted yarn structure immersed at 103°C and foamed at 20.7 MPa and 108°C. [Figure 21D] Figure 21D is a perspective view of a twisted yarn structure immersed at 102°C and foamed at 20.7 MPa and 108°C. [Figure 22] Figure 22 is a schematic diagram of an apparatus for measuring circumferential shear strain. [Figure 23] Figure 23 is a bottom and inner perspective view of a footwear product configured as a right-side shoe, including the upper and sole structures, the sole structure containing anisotropic foam. [Modes for carrying out the invention]

[0028] The following description and accompanying drawings disclose various embodiments or configurations of midsoles comprising various thread structures. While the embodiments are disclosed in relation to sports shoes such as running shoes, tennis shoes, and basketball shoes, the concepts related to the shoe embodiments may apply to a wide range of footwear and footwear styles, including, for example, cross-training shoes, football shoes, golf shoes, hiking shoes, hiking boots, ski and snowboard boots, soccer shoes and cleats, walking shoes, and track cleats. The concept of shoes may also apply to footwear products that do not consider athletic use, including dress shoes, sandals, loafers, slippers, and high heels.

[0029] Where the term “about” is used herein, it refers to a variation in a numerical quantity that may occur due to careless errors in typical measurement and manufacturing procedures used for footwear or other products, which may include embodiments of the disclosure herein, or due to differences in the purity of the manufacturing, source, or materials used to produce a composition or mixture or to carry out a method. Throughout this disclosure, the terms “about” and “approximately” refer to a range of ±5% of the numerical value preceding the term.

[0030] This disclosure relates to footwear manufactured using supercritical foaming technology. The present invention relates to an adjustable midsole. In particular, the midsole of the present invention may be manufactured using supercritical technology and an anisotropic foam which can be produced by twisting together one or more polymer yarns to form a thread structure. For example, a yarn structure is pre-oriented by using a braiding technique or twisting technique as described herein and impregnated with a supercritical fluid and / or superheated fluid to form an anisotropic foam. The pre-oriented anisotropic foam blank is compressed into the shape of a midsole without losing the performance advantages of a multi-component midsole to form an adjustable midsole.

[0031] The midsole may be a single polymer material or a blend of materials such as EVA copolymer, thermoplastic polyurethane (TPU), polyester block amide (PEBA) copolymer, and / or olefin block copolymer. Furthermore, the midsole may be subjected to supercritical gases such as CO2, N2, or mixtures thereof, for example, EVA, TPU The midsole may be formed by foaming a material such as TPE or a mixture thereof, for example, by supercritical foaming, such as physical foaming or chemical foaming. In such embodiments, the midsole may be formed by autoclave, injection molding apparatus, or supercritical foaming. It can be manufactured using a process carried out in any sufficiently heated / pressurized vessel, which can mix a field fluid (e.g., CO2, N2, or a mixture thereof) with a polymer material (e.g., TPU, EVA, polyolefin elastomer, or a mixture thereof).

[0032] In this specification, "yarn," "fiber," or "filament" The term is used interchangeably and refers to an elongated piece of material. Figure 1 shows a cross-section of a yarn 100 containing a single core 104. A yarn 100 containing a single core 104 is a single yarn. This is called (monoyarn) 108. Monoyarn 108 generally consists of a single material. In some embodiments, monoyarn 108 may be formed from polymer materials such as polyester, polyethylene terephthalate (PET), or polyethersulfone (PES). However, monoyarn 108 may be formed containing one or more different materials.

[0033] Figure 2 shows another cross-sectional view of multiple polymer yarns 200, which include polymer yarns 202 having various properties. The multiple polymer yarns 200 include a first polymer yarn 204 having a first property, a second polymer yarn 208 having a second property different from the first property, and a third polymer yarn 212 having a third property different from the first and second properties. In some embodiments, the multiple polymer yarns 200 may be formed from the same material or from two or more different materials. The multiple polymer yarns 200 may include polymer yarns having various properties or various visual characteristics. For example, the polymer yarns 202 of the multiple polymer yarns 200 may be, but are not limited to, thermoplastic polyurethane (TPU), thermoplastic elastomer (TPE), thermoplastic copolyester (TPC), and polyamide (nylon), and may be formed from any one or combination of polymers and / or any other suitable materials.

[0034] In some embodiments, the multiply polymer yarn 200 may be formed from polymer yarns 202 having the same diameter, or the multiply polymer yarn 200 may be formed from one or more polymer yarns 202 having different diameters. In some embodiments, the multiply polymer yarn 200 may be formed from polymer yarns 202 having the same or different tear strengths. In some embodiments, the multiply polymer yarn 200 may be formed from polymer yarns 202 having the same or different denier, i.e., the density of the single strand of yarn. Several embodiments In some embodiments, the multiply polymer yarn 200 may be coated with different substances or materials, and the thickness of the coating may vary among the polymer yarns 202. The multiply polymer yarn 200 may be formed from polymer yarns of the same or different colors. In some embodiments, the multiply polymer yarn 200 may include polymer yarns 202 with various properties such as material, diameter, tear strength, denier, coating, and color, but are not limited to these.

[0035] Polymers are substances or materials consisting of repeating chains of monomers, such as homopolymers or copolymers. Natural polymers include silk, wool, rubber, and cellulose. Natural materials include proteins and other naturally occurring materials. Synthetic polymers are derived from petroleum and are manufactured artificially. Synthetic polymers are classified into four distinct groups: thermoplastic polymers, thermosetting polymers, elastomers, and synthetic fibers.

[0036] Under applied heat, thermoplastic polymers can be either amorphous or crystalline. Thermoplastic polymers become flexible at high temperatures and solidify when cooled. For example, Figure 1 shows a cross-section of a yarn 100 containing a thermoplastic polymer core 112.

[0037] The thermoplastic polymer core 112 may contain synthetic thermoplastic polymers such as thermoplastic polyurethane (TPU), polyethylene (PE), polystyrene (PS), polyamide (nylon), polylactic acid (PLA), polypropylene (PP), polyvinyl chloride (PVC), and polycarbonate (PC). The thermoplastic polymer may be present in a composition of about 5% by weight to about 100% by weight, based on the total weight of the thermoplastic polymer.

[0038] Generally speaking, thermosetting polymers are polymers obtained by irreversible curing. Initially, thermosetting polymers behave like thermoplastic polymers before curing occurs. After curing is performed by heat or appropriate radiation, irreversible curing occurs in the thermosetting polymer. The initial form of a thermosetting polymer is usually malleable or liquid before curing. Therefore, thermosetting polymers are considered thermoplastic polymers before curing. Thermosetting polymers can include melamine formaldehyde, epoxy resins, polyester resins, polyurethanes, and phenol formaldehyde resins.

[0039] Furthermore, elastomers are a type of polymer that possesses viscoelastic properties. Generally, elastomers can return to their original shape after being stretched or deformed. Yarns containing an elastomer core can, among other things, provide flexibility, strain resistance, and biasing and / or spring-like properties. Elastomer yarns can include, for example, elastene such as Lycra®, or nylon or polyamide materials.

[0040] Referring to Figure 3, the foam blank 300 is an object formed by trapping pockets of gas or gaseous mixture in a liquid or solid. The foam blank 300 consists of multiple void structures 304, It includes multiple cell structures connected by multiple cell walls 312. The multiple cell structures are closed-cell foam 316 or It may be an open-cell foam 320. A closed-cell foam 316 is formed when individual gas pockets are completely surrounded by a solid material. Open-cell foam 320 is formed when the gas pockets are interconnected. For example, the foam blank 300 can be formed from different polymers such as thermoplastic polymers and thermosetting polymers. For example, the foam blank 300 has desirable properties such as being lightweight, having good thermal insulation, high strength per unit weight, and high impact strength.

[0041] As described herein, “pellet,” “bead,” “flake,” “powder,” and “granule” are used interchangeably to refer to small particles containing polymer material. Figure 4 shows a thermoplastic polymer core being extruded by polymer pellets 408 having the same material properties. The diagram shows a system 400 for forming a single twisted polymer yarn 404. The twisted polymer yarn 404 may contain at least one polymer core, such as a thermoplastic polymer core. Polymer pellets 408 are fed from a hopper 412 into a barrel 416 of an extruder 420. The pellets 408 are gradually deformed and displaced along the inner wall 422 of the extruder 420 by a rotating screw 424 in which they are melted by a heater 428 positioned along the extruder 420 to produce a molten polymer. The molten polymer exits the screw 424 and moves through a breaker plate assembly 432 containing a filtration media (not shown), such as a screen pack filter, to remove any contaminants in the molten polymer. After passing through the breaker plate assembly 432, the molten polymer enters a die 436. The die 436 gives the polymer yarn 404 its shape, and the polymer yarn exits the die as an extruder 440. Next, the polymer yarn 404 in the extruded product 440 is cooled in a cooling trough (not shown). In some examples, the composite polymer yarn may be produced by extruding a combination of polymer pellets 408 having different material properties.

[0042] The yarn structures described below may include any of the yarns described above, where yarn 100 is a twisted yarn of single yarns 108 or multiple polymer yarns 200, comprising at least one thermoplastic polymer material core having various properties such as material, diameter, denier, tear strength, and color, but not limited to these. Multiple strands of yarns having the same or different properties may be manipulated to produce yarn structures.

[0043] The yarn structure may be a two-dimensional yarn structure, or a three-dimensional yarn structure based on the structural configuration and twisting of the yarn structure. The two-dimensional yarn structure does not extend in two or more directions. The two-dimensional yarn structure may, but is not limited to, non-woven yarns, woven yarns, braided yarns, or lace yarns that extend along a plane. This includes laced yarns and knitted yarns. Three-dimensional yarn structures extend in three directions, regardless of whether the yarn structure is made in a single-step or multi-step process. Examples of three-dimensional yarn structures include, but are not limited to, three-dimensional braided structures, over-braided structures, multi-layer weft-knits, spacer warp knits, and three-dimensional woven structures.

[0044] Figure 5 shows the melt blowing process 500 for producing nonwoven yarn 504. The melt blowing process 500 involves melting the raw materials into a web structure 50 Convert to 8. The first step 510 includes feeding a low-viscosity raw material (not shown) into a hopper 512 to melt it and extruding it through an extruder 516 similar to the extruder 420 in Figure 4. The second step 518 involves feeding die holes in a spinneret 524. The third step includes forming an extruded filament 520 from molten material passing through a hole 522. In the third step 526, the extruded filament 520 is directed toward the die 534 by primary air streams 528. The primary airflow 528 is blown at high speed and high temperature to rapidly and without cooling the extruded filament 520 coming out of the spinneret 524. The temperature of the primary airflow 528 can be measured by a thermocouple (not shown), and the temperature of the primary airflow 528 is approximately equal to or higher than the temperature of the molten raw material of the extruded filament 520. The extruded filament 520 and the primary airflow 528 converge into the die 534 to form a fiber stream 532, which exits through the outlet 535 of the die 534. In the fourth step 530, a secondary airflow 536 having a lower temperature than the primary airflow 528 is applied to the fiber stream 532 to form multiple fibers 538. The secondary airflow 536 can be generated from ambient air and can be applied in a turbulent manner. In the fifth step 540, the multiple fibers 538 are received by the receiving side 542 of a collector or netting machine 544. The die-collector distance 546 is defined between the outlet of the die 534 and the receiving side 542 of the collector 544. The collector 544 is located downstream of the outlet 535 of the die 534. For example, the collector 544 may be provided as a roller such as a calendar roller or a rotating drum. The collector 544 forms a web structure 508 by distributing and / or diffusing the multiple fibers 538 along the collector 544. In the sixth step 548, the web structure 508 is transferred onto a winding machine 550 that winds the web structure 508 to form nonwoven yarns 504. The fabricated body includes a die side 552 which is outside the web structure 508 and a collector side 554 which is inside the web structure 508. For example, the properties of the web structure 508 include the polymer melt temperature, polymer throughput rate, and primary The melt-blowing process 500 is controlled by the selection and combination of several process variables, such as primary air temperature, primary air flow rate, and web-collector distance. The aforementioned process variables determine the morphology and shape, for example, diameter, of the multiple fibers 538 that form the nonwoven yarn 504. For example, increasing the die-collector distance 546 allows the multiple fibers 538 to be longer than necessary to become entangled by exposure to the secondary airflow 536, resulting in increased fiber entanglement to provide a thicker, softer web structure. Furthermore, the die-collector distance 546 may be increased to avoid fiber laydown irregularities, such as bunching or chunking, when the multiple fibers 538 are entangled and collected. Furthermore, increasing the die-collector distance 546 improves fiber cooling by extending the duration for which multiple fibers 538 are exposed to ambient air and / or secondary airflow 536. In contrast, a die-collector distance 546 generally results in reduced fiber entanglement, increased web structure rigidity, and improved barrier properties of the web structure.

[0045] Referring to Figures 6A to 6C, and particularly in relation to Figure 6A, the bundled yarn 600 may be formed from a plurality of yarns 604 arranged along a central axis CA. The plurality of yarns 604 may have different material properties, as described above and herein. Figure 6B shows a plurality of yarns 604 twisted counterclockwise 606 to form a twisted yarn structure 608. A twisted yarn structure 608 twisted counterclockwise is known as an S-twist yarn. In some embodiments, the plurality of yarns 604 may be twisted clockwise to form a Z-twist yarn. The twisted yarn structure 608 may be provided in a variety of configurations and may take alternative forms other than those shown herein. For example, a bundled yarn 600 of a plurality of yarns 604 can be formed by bundling two or more twisted yarns of a single yarn 108 shown in Figure 1, which includes a single thermoplastic polymer core. Specifically, referring to Figure 6C, the multiple yarns 604 are twisted by axial tension applied along a central axis CA that is located in the center of the multiple yarns 604 and extends along the longitudinal direction of the twisted yarn structure 608 through its opposing ends. The multiple yarns 604 are twisted either clockwise or counterclockwise, and as a result, each yarn 614 of the multiple yarns 604 is twisted along the central axis CA as shown in Figure 6C. In contrast, a helical axis HA is defined, which is positioned at a helical angle of 612. Each yarn 614 forms a helix structure 616 defined by a helix angle 612. The helix angle 6 of the helix structure 616 produced by the twisted yarn 600 12 may be at least 10 degrees to at least 80 degrees, at least 20 degrees to at least 70 degrees, at least 30 degrees to at least 60 degrees, or in some examples about 45 degrees. Each yarn 614 may have a uniform helical angle 612, or it may have one or more helical angles 612 that are different from each other. A solvent or foaming agent is impregnated into the twisted yarn structure 608 to form a multi-cell foamed structure, and the orientation of the cell growth direction provides anisotropic properties to the foamed structure with respect to the central axis CA and the longitudinal direction. The foamed structure may include unidirectional cell growth, bidirectional cell growth, and radial cell growth. In some embodiments, the direction of cell growth may be at least one of perpendicular, parallel, or inclined with respect to the longitudinal direction of the central axis CA. In some embodiments, there may be multiple cell growth directions that are different from each other, for example, a first cell growth direction perpendicular to the central axis CA and a second cell growth direction that is not perpendicular to the central axis CA. The cell growth directions incorporated into the various entanglements of the yarn structure provide unique anisotropy.

[0046] Referring to Figures 7A to 7E, a method 700 for twisting a yarn structure under controlled rotation and controlled tension is disclosed. In particular, referring to Figure 7A, a first stiff wire 704 and a second stiff wire 706 are used to hold bundles of yarn 708 at each end. The bundles of yarn 708 are depicted in a simplified manner for illustrative purposes, but it will be understood that they can consist of various forms and shapes. Referring to Figure 7B, the yarn bundles 708 are placed in a tubular reservoir 712. 2 includes opposing ends, each having an opening 714. Referring to Figure 7C, both ends of the tubular reservoir 712 are configured to receive septums or plugs 716. The first septum 718 includes an opening 720 that allows a first rigid wire 704 to pass through in order to form a loop outside the tubular reservoir 712. The second septum 722 includes a larger opening 724 for accommodating a small cut test tube 726, and Two stiff wires 706 pass through a small cut test tube 726. The second stiff wire 706 defines a fixed end 728, and the first stiff wire 704 defines a twisted end 730 having a loop to which a weight 734 is attached to apply axial tension to the yarn bundle 708. Referring to Figure 7D, with the weight 734 attached, the yarn bundle 708 is twisted under controlled rotation and tension. Referring to Figure 7E, after the yarn bundle 708 has been twisted to the desired degree (which may be measured in radians or angles), the weight 734 is removed, and the bundle of twisted yarn 738 is covered with aluminum foil 742, shown translucently for illustrative purposes. A solvent such as styrene 744 is injected into a tubular reservoir 712 through the small cut test tube 726 to saturate and coat the bundle of twisted yarn 738. Next, the tubular reservoir 712 containing the solvent 744 and the twisted yarn 738 is placed in an autoclave or reactor 746 to initiate the foaming process, which involves a controlled application of temperature and pressure, such as exposure to high temperature and high pressure for a predetermined period of time in one or more cycles. The foam blank 752 is formed by reducing the pressure by releasing the pressure through a control valve 756.

[0047] In some embodiments, the yarn may be knitted to manipulate the yarn structure. The knitted yarn structure can be formed by interlocking the yarns to form loops, and thus the knitted yarn structure can be provided in a variety of configurations. The knitting process involves interlocking the yarns so that they extend parallel to each other. The knitting process can be modified, for example, in other embodiments, depending on the direction of loop formation, the density of loop formation, and the variation in loop shape. Figures 8A-G show the stitch structure of the knitted yarn structure 800. Figure 8A shows the rib stitch 804. Figure 8B shows the pearl stitch 808. Figure 8C shows the welt stitch 812. Figure 8D shows the interlock stitch 816. Figure 8E shows a tuck stitch 820. Figure 8F shows a plain stitch 824. Therefore, different stitching configurations, combinations, and materials are used. By applying this to multiple layers, various characteristics can be assigned to each layer.

[0048] In general, weft knitting 828 and warp knitting 832 are two main methods by which yarn can be supplied to a needle for the formation of a knitted yarn structure. As shown in Figure 8F, weft knitting method 828 is achieved by forming multiple loops 836 along the horizontal direction HD using a needle (not shown). In weft knitting method 828, the multiple loops 836 are formed from a single common yarn along the horizontal direction HD and using specific needleling patterns. The yarns are arranged in rows in a continuous manner. The flat knitting method 828 can be achieved using a circular knitting machine or a flatbed machine. Referring to Figure 8E, the warp knitting method 832 is achieved by forming loops in the vertical direction VD. The yarns interlock perpendicularly along the vertical direction VD, and the multiple loops 836 are formed from a combination of several separate yarns arranged longitudinally along the vertical direction VD and oriented parallel to each other. The warp knitting method 832 is achieved using a raschel machine. It is possible.

[0049] In some embodiments, as shown in Figure 8G, a spacer knit 84 Using 4, an ultralight yarn structure can be created. The spacer knit 844 comprises a first substrate layer 848 and a second substrate layer 852. The first substrate layer 848 and the second substrate layer 852 have multiple weft yarns and / or includes a warp yarn structure. Multiple spacer yarns 856 These are arranged perpendicularly along the longitudinal axis VA between the first substrate layer 848 and the second substrate layer 852, forming a plurality of air traps 858. The faces 854 of the first substrate layer 848 and / or the second substrate layer 852 can be woven into various structures, such as a hexagonal mesh or a chain mesh, to manipulate the orientation of the plurality of spacer threads 856 along the transverse direction (shown in Figure 9) or the warp direction (shown in Figure 9). The orientation relative to the longitudinal axis VA can be manipulated to change the shrinkage strain of the plurality of spacer threads 856.

[0050] Referring to Figure 9, a single yarn 108 (see Figure 1) or a multi-ply polymer yarn 200 (see Figure 2) can be woven to form a woven yarn structure 900. The woven yarn structure 900 may be provided in various configurations and may take forms other than those shown and described herein. Yarns arranged in the horizontal direction HD or the weft direction WED are called weft yarns 902. Yarns arranged in the vertical direction VD or the warp direction WAD This is called warp yarn 904. It is the circumference of warp yarn 904 that creates the edge 908 of the fabric. The weft thread 902 that is wrapped around the weft is called the selvedge 912. In some embodiments, the weaving method includes two separate sets of threads that are woven perpendicularly to form a woven structure 900. Thus, the two separate sets of threads are woven together to produce a plain weave structure, a satin weave structure, or a twill weave structure. The weaving process then orients the yarns into a vertical cross pattern 916, allowing the woven structure 900 to maintain a thin profile, but also limiting the elasticity of the woven structure 900.

[0051] In some embodiments, the yarn is woven on a weaving machine such as a shuttle type, circular type, or narrow type. It may also be woven by (not shown). Shuttle looms are generally electronically controlled and configured to weave a tight warp and weft pattern. Shuttle-type looms have a narrow section of wood or plastic with notches at the ends to hold the threads, which automatically moves back and forth between the vertical warp threads to weave through the horizontal weft threads. Conventional circular looms A loom is generally electronically controlled and features two or more shuttles that move simultaneously within a circle to weave the weft threads into a portion of the warp threads. While electronic looms can employ various mechanisms, the basic principle for creating woven fabric structures remains the same. Non-electric, manually operated machines can also be used for weaving, similar to looms. A loom is a device that weaves by applying tension to the warp threads to facilitate the weft thread weaving. While the orientation or shape of various looms can differ, their basic function remains the same.

[0052] In some embodiments, the knitted yarn structure 800 in Figures 8A to 8G or the woven yarn structure 900 in Figure 9 can have various properties by using various materials, various yarn thicknesses, or various colors. Different properties include, for example, yarn count, twist in yarn, yarn strength, torsional properties, elongation, elasticity, tear strength, and bending properties. It can be listed.

[0053] Referring to Figures 10A-C, a braided yarn structure 1000 can be formed by braiding multiple twisted yarns. Referring to Figure 10A, the braided yarn structure 1000 may be provided in various configurations and may take forms other than those shown herein. The braided yarn structure 1000 consists of a first yarn 1004, a second yarn 1008, and a third yarn 1012. Referring to Figure 10B, the first yarn 1004 passes over the second yarn 1008 and under the third yarn 1012. The third yarn 1012 passes over adjacent yarns. In the illustrated embodiment, the first yarn 1004 passes under the second yarn 1008. The yarns 1004, 1008, and 1012 are braided continuously along the central axis CA, thereby allowing the braided yarn structure 1000 to distribute the tensile load more uniformly. The braiding is defined by the braiding angle 1016, which can be expressed as the angle between the central axis and the helical axis HA. The helical axis HA is defined by the helical twisting of the continuous yarn structure. Referring to Figure 10C, the braided yarn structure may be foamed by a supercritical CO2 foaming process to form a foamed braided yarn structure 1020. The supercritical CO2 foaming process is performed under supercritical conditions. This enables the diffusion and solubilization of CO2 molecules within knitted yarn structural materials, as well as the generation of CO2 bubbles within the material, under supercritical conditions. It is caused by a rapid decrease in pressure.

[0054] In some embodiments, the two-dimensional braided structure comprises axial yarns aligned with the axial load direction and braider yarns oblique to the axial yarns, forming various braided structures. The two-dimensional braided structure may be a linear, curved product, or a plane shell. Regular braiding is not limited to this. Different braided structures such as regular braid, diamond braid, and Hercules braid are shown with different braided angles 1016 It can be created in this way. The diagonally intersecting braiding angles 1016 may be at least 1 degree, at least 10 degrees, at least 20 degrees, at least 30 degrees, at least 40 degrees, at least 50 degrees, at least 60 degrees, at least 70 degrees, at least 80 degrees, or at least 89 degrees. Most of the braiding angles 1016 are distributed between 30 and 80 degrees from the central axis CA. The central axis CA is the orientation in which the braided yarn structure 1000 is formed.

[0055] As described herein, “circular braid,” “round braid,” or “tubular braid” are used interchangeably to refer to a braided structure formed around a circular profile. Therefore, the braided structure 1000 in Figure 10 may be used to form a circular braid by weaving threads together according to known methods. Simultaneously, the braided structure can be manufactured using circular braiding while maintaining all braided threads under axial tension. In some embodiments, the axial tension may be changed or varied, or it may be maintained at a constant level over a period of time or throughout the entire process. For short lengths of hand-knitting yarn, individual weights can be used to add and / or adjust tension to the yarn by adding or removing weights as needed. In some embodiments, the yarn is placed around a core or mandrel and knitted in a straight line, for example, from the top end to the bottom end. This hand-knitting method is known as maypole knitting, and this principle is used for over-braiding of different structural profiles. It is used.

[0056] Referring to Figures 11A-F, the braiding machine 1100 may be used to form tubular braids. The braiding machine 1100 utilizes a braiding disc 1104 manufactured from a firm, dense foam having multiple notches 1106 around a periphery 1108, which allows for the creation of the tension required for the braiding threads. The braiding disc 1104 is typically manufactured in a disc shape to allow for the braiding of tubular braid profiles, but the braiding disc 1104 may also be rectangular or square, which provides the ability for the braiding to create flat braids.

[0057] Referring to Figure 11A, eight strands of yarn may be tied together at one end by a knot, or bobbins (not shown) may be used to hold the yarns together and prevent tangling. In some embodiments, the braid (not shown) may be tied to a knot to apply tension to the yarn in a direction perpendicular to the horizontal axis HA defined by the braiding machine 1104. Referring to Figure 11B, in the braiding machine 1100, the first yarn 1110, the second yarn 1112, the third yarn 1114, the fourth yarn 1116, the fifth yarn 1118, the sixth yarn 1120, the seventh yarn 1122, and the eighth yarn 1124 are arranged within a plurality of notches 1106 around a perimeter 1108 called the warp 1128. The braiding machine 1104 of this disclosure includes 32 notches and eight strands of yarn. A knot 1132 is placed in a central hole 1136 on a braiding disc 1104, and the eight twisted threads are divided into four subgroups, each having two twisted threads. For example, the first subgroup 1140 includes the first thread 1110 and the second thread 1112, the second subgroup 1144 includes the third thread 1114 and the fourth thread 1116, the third subgroup 1148 includes the fifth thread 1118 and the sixth thread 1120, and the fourth subgroup 1152 includes the seventh thread 1122 and the eighth thread 1124. The first subgroup 1140 is held by a notch 1106 located at the first position 1160 adjacent to the first dot 1162; the second subgroup 1144 is held by a notch 1106 located at the second position 1164 adjacent to the second dot 1166; the third subgroup 1148 is held by a notch 1106 located at the third position 1168 adjacent to the third dot 1170; and the fourth subgroup 1152 is held by a notch 1106 located at the fourth position 1172 adjacent to the fourth dot 1174. For example, the first subgroup 1140, which includes the first yarn 1110 and the second yarn 1112 at the first position 1160, is held within the notch adjacent to the first dot 1162. The first yarn 1110 is held within the notch located to the left of the first dot 1162, and the second yarn 1112 is held within the notch located to the right of the first dot 1162.Referring to Figure 11C, with the first dot 1162 facing upwards and the third dot 1170 facing downwards, the sixth thread 1120, held in the notch 1106 located to the left of the third dot 1170, moves directly across the horizontal axis HA of the disk and is held in the notch located to the left of the first thread 1110, which is located to the left of the first dot 1162. Referring to Figure 11D, the second thread 1112, located to the right of the first dot 1162, moves directly across the horizontal axis HA of the disk to the notch 1106 located to the right of the fifth thread 1118. Referring to Figure 11E, the braiding disc 1104 is rotated a quarter turn clockwise so that the fourth dot 1174 faces upwards and the second dot 1166 faces downwards. The braiding process in Figures 11C and 11D is repeated by moving the leftmost thread at the bottom left across the horizontal axis and positioning it adjacent to the leftmost thread at the top left, then moving the rightmost thread at the top right across the horizontal axis and positioning it adjacent to the rightmost thread at the bottom right, thereby forming the braided structure 1000 in Figure 10 along the product axis. The product axis PA extends perpendicularly to the braiding machine 1104. Referring to Figure 11F, the braiding machine 1104 is rotated another quarter turn clockwise, and the braiding process in Figures 11C and 11D is repeated.

[0058] In some embodiments, the braided profile is a horn gear Braiding profiles can be created by braiding machines such as horn gear braiders, maypole braiders, square braiders, Wardwell rapid braiders, and high-speed programmable logic controller braiders, but are not limited to these. The general operation of a braiding machine begins with the yarn being wound onto bobbins, the bobbins being mounted on a carrier, and the carrier being mounted on the braiding machine to generate the braided profile.

[0059] In some embodiments, but not limited to them, the braided profile may include different properties such as different materials, thicknesses, and colors. The material may have frictional properties, flexural properties, tensile properties, torsional properties, modulus of elasticity, and breaking elongation. It can include different polymer cores having different mechanical properties such as extensions, plasticity, elastic limits, breaking points, and elongation. For example, a knitted yarn structure 1000 can be formed using three twisted yarns having various properties. The first yarn may have a thicker diameter than the second and / or third yarns. The second yarn contains a different material compared to the first and / or third yarns. The third yarn contains the same type of material as the first yarn but has a different diameter. Thus, by knitting together various yarns, a yarn profile can be created based on the application of the knitted yarn structure 1000.

[0060] Referring to Figures 12A-D, sections of yarn such as the twisted yarn structure 608, the knitted yarn structure 800, and the knitted yarn structure 1000 can be extended by securing adjacent sections of yarn with knots 1200. The knots 1200 can include any of a variety of well-known knot configurations, including the double fisherman's knot, Eskimo bowline knot, double figure-eight knot, fisherman's knot, half hitch knot, calmie loop knot, overhand knot, overhand loop knot, leaf knot, thief knot, square knot, plafond knot, and friendship knot. In some embodiments, the outer layer of the knot 1200 may be heat-sealed at a specific temperature and / or pressure to maintain its shape permanently or semi-permanently.

[0061] As used herein, "foaming agent," "solvent," "pneumatogen," or "blowing agent" are interchangeable and refer to substances capable of generating cellular structures during the foaming process. Foaming agents include physical blowing agents and chemical blowing agents. Contains an agent, or a mixed physical-chemical blowing agent. These may be the case, but are not limited to these.

[0062] In some embodiments, a single type of blowing agent can be used. Examples of physical blowing agents include, but are not limited to, pentane, isopentane, cyclopentane, chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and liquid carbon dioxide (CO2). The blowing process of physical blowing agents is irreversible and endothermic. Examples of chemical blowing agents include, but are not limited to, isocyanates, polyurethanes, azodicarbonamides, hydrazines, sodium bicarbonate, and other nitrogen-based materials.

[0063] The blowing agent compound may comprise at least two chemical substances, at least two physical substances, or a mixture of a physical blowing agent and a chemical blowing agent. The blowing agent compound may comprise blowing agents with different properties, such as activation temperature. That is, the blowing agent compound temperature is... The activation temperature can be defined as the average of the different activation temperatures of the blowing agents contained in the compound. The average can be calculated on a basis of per unit mass or per unit volume. The range of activation temperatures of the blowing agents can differ from one another, for example, about 5°C, or about 10°C, or about 30°C. In this way, foamed structures with specific properties can be achieved by selecting blowing agents having a particular activation temperature. The compound can be combined with physical and chemical blowing agents to balance each other with respect to the thermal energy released and absorbed throughout the foaming process, thereby minimizing temperature fluctuations and improving the thermal stability of the compound and / or the resulting foam.

[0064] A foaming agent is considered effective if the expansion of the total volume results in an increase of at least 10 percent compared to the initial volume of the sample before foaming. For example, a foaming agent may be sufficient to expand the volume of the sample from its initial volume to its final volume. The final volume may be approximately 10 percent or more, approximately 20 percent or more, approximately 30 percent or more, approximately 50 percent or more, approximately 100 percent or more, or approximately 300 percent or more of the initial volume before foaming.

[0065] In thermoplastic foaming, it is important to obtain a foam having a thin polymer wall covering each cell. To provide such a structure, the cell morphology must be controlled by varying the temperature. For example, if the temperature is too high, the melt strength of the polymer may induce cell rupture. On the other hand, if the temperature is too low, cell growth may be suppressed, resulting in insufficient cell growth within the foam blank.

[0066] The characteristics and subsequent applications of a foam blank are determined by the material, the molecular structure of the material, the concentration or amount of the material, and the reaction temperature of the material for the yarn. Various configurations of the yarn structure can be selected and designed to form multi-cell foams with various advantageous properties, by selecting the structure, material, and blowing agent. For example, the concentration or type of blowing agent can affect the cell size, expansion rate, and porosity of the multi-cell foam. Similarly, the weight percentage or concentration of the polymer core can affect the porosity of the multi-cell foam.

[0067] The foam blank provides desirable properties within the midsole by enhancing hardness, water resistance, rigidity, cushioning, sound dampening, and impact dampening. Generally known foam materials have a convex cell shape and exhibit a positive Poisson's ratio, defined as a negative value obtained by dividing the lateral strain by the axial strain when an axial load is applied. Materials containing foam contract laterally in response to axial stretching and expand laterally in response to axial compression, resulting in a positive Poisson's ratio. The range of Poisson's ratio for typical polymer foams is 0.1 to 0.4. For example, foams undergo permanent and material property changes when tension is applied to them at high temperatures. Depending on the direction of tension, unidirectional or bidirectional anisotropic foams can be formed.

[0068] Typically, foamed structures are isotropic. Isotropy refers to the property of a material that exhibits uniform behavior in all directions due to its crystalline structure. Isotropic materials enable the foaming of foams that have the same behavior and material properties in the same direction, and the Poisson's ratio in three dimensions is approximately -1.0 to 0.5. By predetermining the orientation of the cell structure, the advantages of foamed multi-cell filament structures can be further utilized. Foamed structures or foamed materials whose properties depend on the orientation in which they are measured are described as anisotropic. Anisotropy is defined as the tendency of a material to react differently to stress applied in different directions. Anisotropy in cell shape can be easily measured by the ratio of the maximum cell dimension to the minimum cell dimension (referred to as the shape anisotropy ratio R). The anisotropy ratio of a typical foam is approximately 1.3, and this ratio typically varies between approximately 1 and approximately 10, with the anisotropy ratio R increasing with cell size and decreasing with density. The anisotropy ratio R can be expressed in terms of Young's modulus. The ratio of Young's moduli provides the anisotropy ratio R.

[0069] The anisotropic behavior of the foam structure may be introduced in one or more directions by the release of confinement. Methods for increasing the anisotropy ratio of the polymer foam include via a mold, via a multiphase structure having various components, or via fibers or filaments along the cell rise direction. This involves restricting cell growth to one direction by pre-orienting the cells. The process of increasing the anisotropy ratio of polymer foams can be inferred from an understanding of the linear elasticity, non-linear elasticity, plastic collapse, brittle crushing model, and fracture toughness of anisotropic foams.

[0070] In some embodiments, freeze-casting techniques can be used to produce foams having complex three-dimensional foam structures that can be adjusted during the solidification process. Freeze-casting techniques offer various advantages, such as the volume, shape, and orientation of the cell structure, which can be adjusted by changing the suspension characteristics (e.g., liquid type, additives, particulate matter fraction, etc.) and solidification characteristics (e.g., rate, temperature, orientation, external force field, etc.). Various solidification methods, such as unidirectional, bidirectional, radial, radial-centered, and dynamic freezing methods, have been studied as means of controlling porosity and microstructure during the freezing process.

[0071] Figure 13 shows thermoplastic polymer yarn specimen 130 Process 1300 for foaming 4 is shown. Process 1300 involves polymer saturation or impregnation of the yarn sample 1304 with a blowing agent 1308. The blowing agent 1308 may be a physical blowing agent, a chemical blowing agent, or a mixture of a physical blowing agent and a chemical blowing agent. Process 1300 can be induced by increasing the temperature and pressure beyond critical values ​​to create a supersaturated polymer-blowing mixture. The process further includes the generation of an agent mixture. In addition, process 1300 includes cell nucleation or cell growth 1320 of the thermoplastic yarn sample 1304 through a rapid depressurization 1324 represented by a cloud-like figure by the operation of a valve 1328, as represented by the expansion of the exemplary yarn sample 1304 in Figure 13. Furthermore, process 1300 includes cell stabilization in which the pressure and temperature are brought to ambient pressure and ambient temperature in order to form a foamed structure 1332. Well-known batch foaming is applied in two different ways, including the pressure-induced method and the temperature-induced method. In the pressure-induced method, as shown in Figure 13, the first step 1350 includes a yarn sample 1304 saturated with a foaming agent 1308. The second step 1354 includes cell nucleation 1320 of the thread sample 1304 induced by the foaming agent 1308 via a rapid depressurization 1324 caused by the operation of the valve 1328. The rapid depressurization 1324 of the system to ambient atmospheric pressure initiates the foaming process to generate a foamed structure 1332.

[0072] In the temperature-induced method, the process is similar to the pressure-induced method, but at a lower temperature. After saturation is complete, the polymer sample 1304 is placed in an oil bath at a temperature higher than the ambient temperature for a certain period of time, which induces cell nucleation and growth. For example, the temperature of the oil bath may be maintained between 80°C and 150°C, but is not limited to this. After the bubbles (cells) have been formed, the foamed structure 1332 is placed in a cooling bath in water or a solvent.

[0073] As used herein, supercritical fluids are understood to be substances whose temperature and pressure are above their critical point, where distinct liquid and gas phases do not exist, and below the pressure required to compress the substance into a solid. Supercritical fluids dissolve materials such as liquids and solids. Supercritical fluids can undergo a process where, near their critical point, small changes in pressure or temperature can lead to large changes in density. Carbon dioxide and water are the most commonly used supercritical fluids. Supercritical carbon dioxide has a critical point of 7.4 MPa at 31°C. Superheated water has a critical point of 22 MPa at 374°C and is similar to organic solvents.

[0074] Furthermore, when used herein, a superheated fluid is understood to be a substance in equilibrium with vapor at its saturated vapor pressure. For example, superheated water is a well-known superheated fluid. Superheated water is configured such that the overpressure raises the boiling point and the liquid water is stabilized or meta-stabilized in an environment in equilibrium with vapor, which can be obtained by heating water in a sealed container with headspace. While a superheated fluid or moisture interacts with a foamed structure, the relatively high temperature of the superheated fluid causes trapped gas within the foamed structure to expand, enlarging voids and thereby reducing the overall density of the foamed structure. With respect to supercritical states, a medium such as CO2 or N2 rises above its critical point and, through diffusion into the foamed structure, allows access to small voids that are inaccessible below the critical point, thereby partially increasing the density of the supercritical medium relatively. When a foamed structure is exposed to a supercritical medium, parts of the foamed structure become plasticized and the foamed structure becomes saturated. In subsequent processes, the foamed structure is confined to a supersaturated state, for example, by reducing the pressure or increasing the temperature, causing nucleation and relative growth of porous cells within the polymer matrix of the foamed structure. Exposure to a supercritical medium and supersaturation reduce the overall concentration of the foamed structure. These properties allow for continuous adjustment of density by varying experimental conditions of temperature and pressure, making each of the supercritical and superheated conditions preferable for carrying out extraction or impregnation processes.

[0075] Figure 14 shows a cross-section of the foamed thermoplastic yarn 1400. The first inner diameter 1404 corresponds to the yarn 100 in Figure 1 before undergoing the foaming process described herein, and the second outer diameter 1408 shows the yarn 100 in Figure 1 after foaming to form the foamed thermoplastic yarn 1400. When the yarn 100 interacts with a supercritical blowing agent such as CO2, the yarn 100 is saturated with a gas beyond the supercritical state. By decreasing the pressure or increasing the temperature, the yarn 100 becomes supersaturated, causing porous cells to proliferate within the polymer matrix. When the yarn 100 is under supercritical conditions, its melting point, heat-glass transition point, crystallization temperature, crystallization rate, and expansion temperature are determined. This alters physical properties such as moisture. Generally, solvent penetration induces swelling by reorienting polymer chains to form a thermodynamically favorable crystalline state. The foaming process increases the diameter and induces a change in diameter, i.e., a change in the polymer yarn from the illustrated first diameter 1404 to the second diameter 1408, while simultaneously increasing the porosity of the structure and decreasing the density of the yarn.

[0076] Referring to Figure 15A-B, to observe the change in diameter 1506 before foaming 1508 occurs and after foaming 1510 occurs, a knot structure understood as a cobra knot formed from polyamide 6 monofilament 1504 is shown. The structure 1500 was processed with polyamide 6 monofilament 1504. The cobra knot structure 1500, formed from polyamide 6 monofilament 1504, was subjected to supercritical carbon dioxide to determine the change in diameter 1506 of the cobra knot structure 1500 during the foaming process. The increase in diameter 1506 of the monofilament yarn 1512 was less than 25%. When the monofilament yarn 1512 was exposed to superheated water and supercritical carbon dioxide, the diameter 1506 of the polyamide 6 monofilament 1504 increased by more than 125%. The combination of supercritical and superheated fluids may be desirable for foams requiring highly porous structures.

[0077] A method for foaming a filamentous structure is described below. The filamentous structure may include any of the filamentous material, filamentous features, and foaming agent described above. Under supercritical conditions, impregnation with a foaming agent causes the material to foam and form at least one foamed region along the filamentous structure. For example, a thermoplastic filament A yarn structure incorporating either of these can be processed under supercritical conditions to produce a multi-cell foam containing multiple cavities. These cavities may include either an open-cell foam structure or a closed-cell foam structure. The introduction of bubbles from the foaming agent induces the formation of the cell structure during the manufacturing process. Once foamed, the foamed multi-cell yarn structure possesses various mechanical properties compared to the non-foamed yarn structure. For example, the foamed structure can impart a combination of increased texture, strength, cushioning, abrasion resistance, and / or other material properties.

[0078] Figure 16 shows an exemplary process 1600 for foaming a yarn structure. The first step 1604 includes selecting a yarn material based on certain properties and characteristics. The yarn material may consist of any of the yarn materials described herein, such as recycled plastic, TPU, or nylon. The selection of a particular yarn can be based on one or more of specific properties and characteristics, such as denier, tear strength, color, and / or thickness. The second step 1606 includes twisting the selected yarns together to form a yarn structure. The selected yarns can be twisted together using any of the methods described above to form a desired yarn structure. The third step 1608 includes inserting the yarn structure into a first shoe midsole mold and placing the first shoe midsole mold containing the yarn structure into an autoclave. The fourth step 1610 includes impregnating and saturating the yarn structure with a substance such as a gas under supercritical conditions, for example, in order to initiate a foaming process. The fifth step 1612 includes foaming of the yarn structure caused by rapid depressurization of the autoclave. The sixth step 1614 includes removing the foamed yarn structure from the autoclave and the first shoe midsole mold. Step 7, 1616, includes placing the foamed yarn structure within a second mold to provide the shape of the midsole. The second compression molding process is carried out at an operating temperature that raises the component temperature of the anisotropic foam blank to at least 30°C above its melting temperature but does not cause its plastic deformation. It will be understood that the melting temperature of the anisotropic foam blank may be determined by the specific material used and / or its properties after foaming.

[0079] In some embodiments, the filament structure includes unidirectional and / or bidirectional orientation. The unidirectional and / or bidirectional filament structure may be pre-oriented within the foam blank to form an adjustable and functional anisotropic foam blank. In some embodiments, the anisotropic foam blank may include a plurality of first cells having a first cell growth orientation and a plurality of second cells having a second cell orientation, wherein the first cell growth orientation is distinct from the second cell growth orientation. The anisotropic cell orientations provided by the various filament structures described above enable the foam blank to have desirable characteristics at ideal locations. The various filament structures and their configurations described above include collapsing structures having flexibility in one or more specific directions, and rebound structures having elasticity in one or more specific directions. ), and support structures having rigidity in one or more specific directions, can be provided to offer specific functions to be contained within the foam blank. Various thread structures and pre-orientation of thread configurations allow specific regions of the foam to exhibit different technical, direction-dependent, and performance characteristics.

[0080] Referring to Figure 17, a high-pressure reactor system 1700 used to manufacture foam blanks is shown. The high-pressure reactor system 1700 includes an inlet valve 1702, an outlet valve 1704, a pressure gauge 1706, a rupture disk 1708, a high-pressure reactor 1710, a thermocouple 1712, and a PID controller (not shown). The inlet valve 1702 may be a needle valve (not shown) that transmits CO2. The pressure gauge 1706 measures the pressure inside the high-pressure reactor system 1700, and the rupture disk 1708, also known as a pressure safety disk, is a pressure-relief safety device that protects the pressurized high-pressure reactor 1710. High-pressure reactor 1710 It includes an internal chamber (not shown) configured to receive a filamentous structure sample or a portion thereof, which can be permeated with supercritical gas to create a foam blank. The high-pressure reactor 1710 is connected to a thermocouple 1712 and a PID controller (not shown) to sense temperature changes and maintain and adjust a specific temperature. The outlet valve 1704 may be a ball valve (not shown) for rapidly reducing the pressure of the reactor, or it may include a needle valve for slower pressure reduction.

[0081] The mechanism of the microcellular structure may differ depending on the method of forming the twisted or braided structure. In this invention, the mechanism of the microcellular structure of anisotropic polyamide filament is investigated by analyzing the degree of crystallinity, the change in diameter after foaming, the change in concentration after foaming, and / or the change in the cross-sectional area after foaming, as determined by differential scanning calorimetry. Figure 18A shows the braided structure 1800 formed by the braiding machine shown in Figure 11 before foaming, and Figure 18B shows the foamed braided structure 1802. When the fiber 1804 containing the braided structure 1800 is pulled under tension, the degree of crystallinity and the diameter of the fiber change based on the strain caused by the tension. The degree of crystallinity can be determined by comparing the density of the sample with the amorphous density of the sample using differential scanning calorimetry. Table 1 shows the relationship between the degree of crystallinity and the change in diameter with respect to strain.

[0082] Table 1: Changes in crystallinity and diameter with respect to strain induced by fibers stretched by tensile force [Table 1]

[0083] The knitted yarn structure 1800 has a filament diameter of 0.56 mm and weighs approximately 1.22 g / cm². 3It has the density of . Firstly, the immersion process involves soaking the braided yarn structure in superheated water in the range of approximately 101°C to approximately 105°C at a pressure in the range of approximately 20.7 MPa (megapascals) to approximately 34.5 MPa for approximately 4 hours. This includes immersing body 1800. Secondly, the foaming process is carried out at a temperature in the range of approximately 106°C to approximately 112°C and a pressure in the range of approximately 20.7 MPa to approximately 34.5 MPa. Foaming occurs by rapid depressurization to form the foamed braided yarn structure 1802. The foamed braided yarn structure 1802 shows an increase in filament diameter from 0.56 mm to 1.57 mm, which is an increase of approximately 180% in filament diameter dimension and 1.22 g / cm³. 3 From 0.332 g / cm³ 3 This is a decrease in density. Therefore, the foamed knitted yarn structure 1802 shows a concentration change of about 60%. In some embodiments, the foamed knitted yarn structure 1802 shows a concentration change of at least 45%, or at least 50%, or at least 60%, or more. It will be understood that the twisted yarn structure 608 can also show a similar change by the techniques described herein, so that the twisted yarn structure 608 can also show a concentration change of at least 45%, or at least 50%, or at least 60%, or more. Furthermore, the foamed knitted yarn structure 1802 shows that the knitting has been energized by maintaining the twist it had before foaming. The increase in fiber area, the change in density, and the porosity of the foamed knitted yarn structure 1802 are shown based on the foaming temperature.

[0084] Table 2: Foamed samples of braided structures [Table 2]

[0085] Figures 19A to 19D show corresponding cross-sectional views of the braided structure foam samples 1 to 4 described above.

[0086] Figure 20A shows the twisted yarn structure 2000 formed using the method shown in Figures 7A to 7E. Firstly, the immersion step involves immersing the twisted yarn structure 2000 in superheated water at a temperature in the range of approximately 101°C to approximately 105°C at an atmospheric pressure in the range of approximately 20.7 MPa (megapascals) to approximately 34.5 MPa for approximately 4 hours. This includes immersion. Secondly, the foaming process is carried out at a temperature in the range of approximately 106°C to approximately 112°C and a pressure in the range of approximately 20.7 MPa to approximately 34.5 MPa. Referring to Figure 20B, foaming occurs by rapid depressurization to form the foamed twisted yarn structure 2002. Table 3 shows the increase in fiber area, change in density, and porosity of the foamed twisted yarn structure 2002 based on the foaming temperature.

[0087] Table 3: Foamed Twisted Structure Samples [Table 3]

[0088] Figures 21A to 21D show the corresponding cross-sectional views of the twisted composite foam samples 1 to 4 described above.

[0089] In this invention, PA-PS (polyamide-polystyrene) composite samples were prepared using the method shown in Figures 7A-7E, and the orientation of the filaments relative to the circumferential shear strain aggregate was investigated. For example, the pitch at which the threads are arranged can lead to insufficient adhesion between filaments in the braided structure during compression. Since the midsoles of footwear products are subjected to repeated compression, it is important to understand the relationship between filament orientation and compression. The filament sample contained 60 filaments with a length of approximately 6.2 cm to 6.6 cm, which were twisted with a suspension mass of 1 kg for 2.5 to 4 full turns. Styrene monomer, 0.3 mol% tert-butylperoxybenzoate initiator, and methanol. The solvent is used to prepare the PA-PS composite sample. First, the PA-PS composite material sample is immersed at 75°C for 24 hours at 27.6 MPa. Second, PS polymerization occurs at 115°C for approximately 4 to 16 hours at 27.6 MPa. After polymerization has occurred, the composite sample is rapidly depressurized to ambient temperature using an outlet valve 1704 in the form of a ball valve (see Figure 17). The change in diameter of the PA-PS composite material sample can be determined by observing the initial radial pitch (Pi) and final radial pitch (Pf), initial height and final height, and measuring the change in rotation. Table 4 shows the relationship between polymerization time, fiber pitch before swelling, pitch after swelling, and change in diameter.

[0090] Table 4: Polymerization Test [Table 4]

[0091] The increased diameter of the filaments corresponds proportionally to the increase in porosity of the yarn structure containing the filaments. That is, a larger increase in diameter corresponds to a larger increase in porosity, which is an important characteristic for suitable foaming applications. The change in filament pitch, i.e., angle, before and after swelling may be a result of the change in diameter. As mentioned above, the pitch of a twisted or knitted yarn structure can cause poor adhesion when compressed. Therefore, it is necessary to understand the relationship between the change in pitch and filament diameter before and after swelling by measuring the circumferential shear strain. As mentioned above, sample 1 was observed to have an initial radial pitch Pi of 37.9 rotations / meter and a final radial pitch Pf of 59.4 rotations / meter, which is a 56.7% increase in radial pitch and a 122% increase in diameter was also observed. In contrast, sample 3 was observed to have an initial pitch Pi of 37.9 rotations / meter and a final radial pitch Pf of 60.5 rotations / meter, which is a 59.6% increase in radial pitch and a 135% increase in diameter was also observed. The main difference between samples 1 and 3 is the polymerization time; sample 3 had a polymerization time of 16 hours, while sample 1 had a polymerization time of only 4 hours. Therefore, it is presumed that the longer polymerization time of the samples allows for a greater increase in radial pitch, and such an increase in radial pitch can lead to a larger increase in diameter. Sample 4 had a polymerization time of 16 hours, and it is understood that a foaming process was carried out, resulting in a diameter increase of 178%, which is significantly larger than the diameter increase of any of samples 1, 2, and 3.

[0092] Figure 22 shows a device 2200 that enables the measurement of circumferential shear strain under compression. The device 2200 includes an upper compression clamp 2202, a lower compression clamp 2204, a sample plate 2208, and a thrust ball bearing 2210. Adhesive 2212 is used to bond the bottom surface 2214 of the thrust ball bearing 2210 to the top surface 2216 of the lower compression clamp 2204. The top surface 2218 of the thrust ball bearing 2210 is bonded to the bottom surface 2220 of the sample plate 2208, and the top surface 2222 of the sample plate 2208 is bonded to the bottom surface 2224 of the sample 2206 by adhesive 2212. The top surface 2226 of the sample 2206 is bonded to the bottom surface 2228 of the upper compression clamp 2202 by adhesive 2212. Adhesive 2212 is used to bond the thrust ball Rotation of the surface around the vertical axis VA is restricted, excluding bearing 2210. The thrust ball bearing 2210 is the only surface that can rotate when subjected to a compressive force to measure circumferential shear strain. The circumferential shear strain can be measured by multiplying the change in angle around the vertical axis due to the thrust ball bearing by the radius of the sample and dividing by the height of the sample, as shown in (Equation 1) below, where R is the radius of the sample, H is the height of the sample, and Δθ is the change in angle due to the thrust ball bearing.

[0093]

number

[0094] For example, a 4-hour PA-PS composite material sample was rotated 15 degrees with a compressive strain of 0.19 mm / mm at a radius of 0.0053 m and a height of 0.011 m. The circumferential shear strain was equal to 0.13, determined by (Equation 1) above. In this way, the compression test can provide a method for measuring the circumferential shear strain during compression and calculating the ideal pitch and / or diameter, which can be derived by using (Equation 1).

[0095] This disclosure relates to footwear products or specific components of footwear products, such as soles. Figure 23 shows an exemplary embodiment of a footwear product 2300, which includes an upper 2302 and a sole structure 2304. The sole structure defines a midsole 2306 and an outsole 2308. The sole structure 2304 includes an anisotropic foam 2310 that provides high cushioning and adjustable deformation of the sole structure 2304. The upper 2302 is attached to the sole structure 2304 and, together with the sole 2304, defines an internal cavity 2312 into which the user's foot can be inserted. For reference, each of the shoes defines a forefoot region 2314, a midfoot region 2316, and a heel region 2318.

[0096] In some embodiments, a midsole 2306 comprising a tunable foam 2310 can provide the advantages of a multi-component sole. Generally, conventional multi-component soles include separate components, such as plates, that are assembled together. In some examples, the plates are sandwiched between the upper and lower segments of the midsole. However, the present invention provides a sole structure 2304 that includes an anisotropic foam 2310, achieving the desired functionality provided by a multi-component midsole but without requiring the manufacture and assembly of multiple components. In other words, without adding any additional components or elements of a multi-component midsole, a midsole 2306 comprising the pre-oriented anisotropic foam 2310 of this disclosure can be formed, i.e., tuned using the methods, materials, and techniques described herein to provide, and even exceed, the performance and functionality of a multi-component midsole.

[0097] In another embodiment, the anisotropic foam 2310 may have one or more adjustable properties that change across the sole structure 2304. For example, the heel region 2318 may have a pre-orientation anisotropic foam having rebounding property and shock-absorbing property. It may include a tropic foam 2310, while the midfoot region 2316 is a preliminary region having greater flexibility, lower stiffness, and / or energy return feature. It may include anisotropically oriented foam 2310. In some embodiments, the sole structure 2304 may consist of a number of anisotropically oriented foams 2310 in the form of segments positioned at specific locations along the heel region 2318, the midfoot region 2316, and the forefoot region 2314, or a combination thereof. In some embodiments, the midsole 2306 may have pre-orientation anisotropy in the forefoot region 2314, the heel region 2318, the midfoot region 2316, or a combination thereof. It is a single, integrated component comprising the pre-oriented anisotropic foam 2310. Therefore, the pre-oriented anisotropic foam 2310 provides the midsole 2306 with selective or adjustable property and functional changes, such as changes in rigidity or flexibility. The pre-oriented anisotropic foam 2310 may be pre-oriented using the twisting or weaving techniques described herein.

[0098] As described herein, multi-cell foam blanks containing polymer yarn structures may exhibit beneficial properties such as ease of manufacture, minimal waste, and versatile design, among other advantages. Furthermore, pre-oriented anisotropic midsoles may enable good waste management and recycling of materials after the shoes are discarded. Sole structures 2304, including midsoles 2306 such as single-layer midsoles, facilitate the separation of materials, allowing thermoplastics to be melted into flakes and fragments. Conventional shoe manufacturing techniques use a variety of machinery and chemicals to produce shoes. On average, shoes contain numerous parts made from a variety of different materials, which contribute to the generation and / or retention of greenhouse gases, including carbon dioxide, in the atmosphere. Moreover, shoes formed by conventional manufacturing techniques and made from multiple components are difficult to recycle, especially when those materials are bonded together, due to the differences in the materials used. As a result, about 80% of sneakers end up in landfills, and shoes decompose over long periods, releasing toxins, chemicals, and fossil fuels into the surrounding environment. In this invention, the sole structure is manufactured from anisotropic foam made from polymer yarn to eliminate or reduce the use of numerous components within the sole structure. Therefore, there is no need to disassemble the sole structure to remove embedded or attached components in order to reuse the shoes. Furthermore, the reduction in the number of components leads to a reduction in transportation and pollution caused by transportation, which is associated with delivering the components to a single assembly location, and may also reduce the number of machines used in one or more factories to manufacture the shoes and their components. In addition, the foaming process and anisotropic foam can provide high stability, durability, and puncture resistance to extend the service life of the shoes. Furthermore, assembling multiple components typically involves the use of adhesives or cements, which can release toxins into the environment at various stages of use, such as during assembly or recycling.The present invention provides a single structure having not many, or fewer, components, which can reduce or eliminate the need for adhesives and / or cement, thereby reducing its environmental impact.

[0099] Any embodiment described herein can be modified to include any of the structures or methods disclosed in relation to various embodiments. Similarly, in some embodiments, materials or construction techniques other than those disclosed above can be substituted or added according to known approaches. Furthermore, this disclosure is not limited to the types of footwear products specifically shown. Moreover, any aspect of a footwear product of any embodiment disclosed herein can be modified to function in any type of footwear, apparel, or other athletic equipment.

[0100] As stated above, although this disclosure is set forth in relation to specific embodiments and examples, it will be understood by those skilled in the art that this disclosure is not necessarily limited in this way, and that a number of other embodiments, examples, uses, modifications, and deviations from embodiments are intended to be encompassed by the claims appended herein.

Claims

1. A step of selecting multiple threads in which at least two threads have different properties from each other, A step of bundling the plurality of threads in order to form a bundled thread structure, To form a twisted yarn structure, the process involves fixing the ends of the bundled yarn structure, applying axial tension to the bundled yarn structure, and rotating the bundled yarn structure to twist the bundled yarn structure together. A step of depositing the twisted yarn structure in a first mold inside an autoclave, A step of applying a supercritical fluid to the twisted yarn structure and allowing the supercritical fluid to permeate and saturate the twisted yarn structure, A step of reducing the pressure in the autoclave in order to cause a foaming process to convert the twisted yarn structure into an anisotropic foam blank, A method for manufacturing a midsole, comprising the step of depositing the anisotropic foam blank into a second mold configured as a midsole for a footwear product.

2. The method according to claim 1, wherein at least one of the plurality of threads is composed of at least one of a thermoplastic polymer, a thermosetting polymer, or an elastomer polymer.

3. The method according to claim 1, wherein the supercritical fluid includes superheated water, supercritical carbon dioxide, or both.

4. The method according to claim 1, wherein the diameter of at least one of the plurality of threads is increased by at least 120%.

5. The method according to claim 1, wherein the density of at least one of the plurality of threads is reduced by at least 50%.

6. A step of selecting multiple threads in which at least two threads have different properties from each other, A step of bundling the plurality of threads in order to form a bundled thread structure, To form a braided yarn structure, the process involves applying axial tension to the bundled yarn structure and twisting the bundled yarn structure together using a braiding technique, A step of depositing the braided yarn structure in a first mold inside an autoclave, A step of applying a supercritical fluid to the braided yarn structure and allowing the supercritical fluid to permeate and saturate the braided yarn structure, A step of reducing the pressure in the autoclave in order to cause a foaming process to convert the braided yarn structure into an anisotropic foam blank, A method for manufacturing a midsole, comprising the step of depositing the anisotropic foam blank into a second mold configured as a midsole for a footwear product.

7. The method according to claim 6, wherein at least one of the plurality of threads is composed of at least one of a thermoplastic polymer, a thermosetting polymer, or an elastomer polymer.

8. The method according to claim 6, wherein the supercritical fluid includes superheated water, supercritical carbon dioxide, or both.

9. The method according to claim 6, wherein the diameter of at least one of the plurality of threads is increased by at least 120%.

10. The method according to claim 6, wherein the density of at least one of the plurality of threads is reduced by at least 50%.

11. The method according to claim 6, wherein the braiding technique is a braided cord braiding technique.

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