Article of footwear

Abstract

To optimize a midsole so as to reduce 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 of and priority to U.S. Provisional Application No. 63 / 388,523, filed July 12, 2022, which is incorporated by reference herein in its entirety. [Background technology]

[0002] FIELD OF THE DISCLOSURE The present invention generally relates to a variety of pre-oriented yarn structures. The present invention relates to an article of footwear comprising an anisotropic foam made from the polyimide.

[0003] Many conventional shoes or other footwear products generally include an upper and a sole attached to the lower end of the upper. Conventional shoes further include an interior space, i.e., a void or cavity formed by the interior surface of the upper and the sole, that receives the user's foot before the shoe is fastened to the foot. 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 sole typically provides stability and cushioning to the user when the shoe is being worn. In some examples, the sole may include multiple components, such as an outsole, a midsole, and an insole. The outsole may provide traction to the bottom surface of the sole, and the midsole may be attached to the interior surface of the outsole. The sole may also include additional components, such as a plate embedded in the sole, to increase the overall stiffness of the sole and reduce energy loss during use.

[0004] The upper generally defines an interior cavity that extends upward from the sole and completely or partially encases the foot. In most cases, the upper extends across the instep and toe regions of the foot, as well as across the medial and lateral sides thereof. Many footwear articles may also include a tongue that extends across the instep region and bridges the gap between the ends of the medial and lateral sides of the upper, defining an opening into the cavity. The tongue may also be located below the lacing system and between the medial and lateral sides of the upper to allow adjustment of the tightness of the shoe. The tongue may further be operable by the user to allow entry or exit of the foot from the interior space or cavity. In addition, the lacing system may allow the user to adjust certain dimensions of the upper or sole, thereby allowing the upper to accommodate a wide variety of foot lasts having different sizes and shapes.

[0005] The upper may include a wide variety of materials that may be selected based on one or more intended uses of the shoe. The upper may also include regions that include various substances specific to certain areas of the upper. For example, additional stability may be added near the front or heel of the upper by providing greater resistance or stiffness. In contrast, other portions of the shoe may include 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 traction with the ground, and a multi-component midsole that provides lever-like assistance and toe stabilization. The multi-component midsole includes a lower midsole cushioning member, an upper midsole cushioning member, and a plate disposed between the upper and lower cushioning members. The plate, typically formed from carbon fiber or other composite material, reduces the kinetic energy and resulting momentum of a user's foot strike. and assist the user in performing less tiring athletic activities.

[0007] While many shoes currently available have various features relating to the properties mentioned above, many shoes, and more specifically their midsoles, could be further optimized. Summary of the Invention

[0008] In some embodiments, a method of manufacturing a midsole includes selecting a plurality of yarns. and at least two of the plurality of yarns have different properties. The method further includes bundling the plurality of yarns to form a bundled yarn structure, and intertwining the bundled yarn structure to form a twisted yarn structure. The intertwining step may be performed by fixing ends of the bundled yarn structure, applying axial tension to the bundled yarn structure, and rotating the bundled yarn structure. The method further includes the steps of depositing the stranded structure in a first mold in an autoclave and forming a stranded structure. and applying a supercritical fluid to the stranded yarn structure. The method further includes applying a supercritical fluid to the stranded structure to infiltrate and saturate the stranded structure with the supercritical fluid, and generating a generator to convert the stranded structure into an anisotropic foam blank. The autoclave is depressurized to allow the foaming process to occur. ) and forming the anisotropic foam blank into an article of footwear. and depositing the foam into a second mold configured as a midsole of the foam.

[0009] In some embodiments, at least one of the plurality of yarns is made of a thermoplastic polymer, a thermoset polymer, or an elastomeric polymer. In some embodiments, the anisotropic foam blank has a first cell growth direction parallel to a longitudinal direction of the stranded yarn structure. In some embodiments, the anisotropic foam blank comprises a second cell growth direction perpendicular to the longitudinal direction of the stranded yarn structure. In some embodiments, the supercritical fluid comprises superheated water or supercritical carbon dioxide, or both. In some embodiments, at least one of the plurality of yarns is In some embodiments, the diameter of at least one of the plurality of yarns increases by at least 120%. In some embodiments, the density of at least one of the plurality of yarns increases by at least 50%. Decreases.

[0010] In some embodiments, a method of manufacturing a midsole includes selecting a plurality of yarns, at least two of the plurality of yarns having different properties. The method includes braiding the plurality of yarns to form a braided yarn structure, and twisting the braided yarn structure using a braiding technique to form a braided yarn structure. Axial tension is applied to the braided yarn structure. The method further includes depositing the braided yarn structure in a first mold in an autoclave and applying a supercritical fluid to the braided yarn structure. The method also includes infiltrating and saturating the braided yarn structure with the supercritical fluid, depressurizing the autoclave to cause a foaming process to convert the braided yarn structure into an anisotropic foam blank, and depositing the anisotropic foam blank into a second mold configured as a midsole for an article of footwear.

[0011] In some embodiments, at least one of the yarns of the plurality of yarns is composed of at least one of a thermoplastic polymer, a thermoset polymer, or an elastomeric 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 yarns increases by at least 120%. In some embodiments, the density of at least one of the plurality of yarns decreases by at least 50%. In some embodiments, the circumferential shear strain of the plurality of yarns is greater than 0.05. In some embodiments, the braiding technique is a braid braiding technique.

[0012] In some embodiments, the tunable midsoles described herein are manufactured using The method includes utilizing an anisotropic foam blank. The anisotropic foam blank is a preform disposed between or within segments of the midsole. Used in place of multi-component midsole constructions, such as to replace The anisotropic foam blank may be formed by twisting together a plurality of yarns in a pre-oriented manner. The anisotropic foam blank may be tunable and pre-oriented to provide cushioning, stability, elasticity, and elasticity. Providing customized local characteristics such as energy dissipation or absorption, puncture resistance, and propulsion Additionally, the anisotropic foam material of the present disclosure reduces the need to assemble or install multiple components, thereby reducing waste associated with excess materials and minimizing energy consumption associated with labor and transportation of assembling such structures.

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

[0014] In some embodiments, the plurality of yarns comprises a polymeric core. The polymeric core comprises a first material. The first material may be a thermoplastic polymer, a thermoset polymer, or an elastomeric polymer. In some embodiments, the thickness, denier, and tear strength of the polymeric core are: Varies based on the material of the polymer core.

[0015] In some embodiments, the core material comprises a second polymeric material, and the second polymeric material is different from the first polymeric material. The core material may comprise multiple materials, or different cores may comprise different materials. The number of cores varies based on the intertwined yarn structure.

[0016] In some embodiments, a solvent or blowing agent is added to the entangled yarn structure. The yarn structure is impregnated to form a multicellular foam, where the orientation of the cell growth direction provides the foam with anisotropic properties. The foam may include unidirectional cell growth, bidirectional cell growth, and radial cell growth. The cell growth direction combined with the various intertwinements of the body provides a unique anisotropy.

[0017] In some embodiments, the intertwined structures and superstrates are A supercritical solvent is applied to a pressurized autoclave, and the molecules of the supercritical solvent rapidly transform into a gas to form a plurality of polyhedral cells within the material of the yarn structure, and the orientation of the cell growth direction is different in the yarn structure. The solvent may be a supercritical fluid such as carbon dioxide or nitrogen, or a solvent such as water. The entangled yarn structure may be a superheated fluid. When the yarn is exposed to both heat and a superheated fluid, an anisotropic foam can form. As a result of the foaming process, the diameter of the yarn can increase by at least 10% or more. Depending on the material and the solvent, the diameter of the foam can show a large increase.

[0018] In some embodiments, the anisotropic foam undergoes a second molding process to compress the anisotropic foam and give the midsole a specific shape. The anisotropic foam may be pre-oriented prior to the second molding process to form the upper midsole. ), a lower midsole, and a plate or other structure within the midsole. It is possible to provide different functionality without including multiple components of the above.

[0019] In some embodiments, the expansion process of a yarn structure involves the selection of yarn material and characteristics of the yarn including, but not limited to, diameter, denier, tear strength, and color. The yarn structure is formed after the selected yarns are twisted in a specific way and pre-oriented in a mold. The mold is placed in an autoclave where the yarn structure is softened and infiltrated with a blowing agent. The blowing agent causes cells to expand in a specific direction during cell nucleation. The foam is then subjected to a second compression molding step to induce foam growth and rapidly depressurize to produce the anisotropic foam. The foam then undergoes a second compression molding step to give the foam the specific shape of the midsole.

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

[0021] In some embodiments, the yarn structure is braided using a Kumihimo disk. It is formed by braiding the yarn. The braiding disk controls the tension. The tension is provided by small weights at the ends of the bobbins.

[0022] In some embodiments, the thread structures are pre-oriented in a mold. The mold defines the forefoot, midfoot, and heel regions of the midsole. The mold contains different thread structures according to the region, such that different thread structures provide different desired functionality, cushioning, and benefits in a particular region. Various types of thread structures can be stacked, bundled, and / or sandwiched to achieve the desired properties and functionality.

[0023] In some embodiments, a second compression molding of the anisotropic foam containing the yarn structure is performed by adjusting the ambient parameters or or during expansion of said yarn at least 40 degrees above the operating parameters. Or after foaming, it is carried out.

[0024] In some embodiments, an article of footwear includes an upper having a forefoot region, a heel region, and a midfoot region, and 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-oriented anisotropic foam is provided in a forefoot segment, a heel segment, and a midfoot segment. In some embodiments, the midsole is a unitary structure having the pre-oriented anisotropic foam in each of the forefoot region, the heel region, and the midfoot region. The midsole has at least one of a flexibility or a stiffness that differs between the forefoot region, the heel region, and the midfoot region. In some embodiments, the midsole includes a plate in contact with the pre-oriented anisotropic foam. In some embodiments, the pre-oriented anisotropic foam is formed by at least one of a braided yarn structure or a twisted yarn structure.

[0026] Other aspects of the method of making the tunable midsole foam herein, including processes, features, and advantages thereof, will be apparent to one of ordinary skill in the art upon review of the figures and detailed description herein, and thus, all such aspects of the process of making the tunable midsole foam are intended to be included in the detailed description and this summary. [Brief description of the drawings]

[0027] [Figure 1] FIG. 1 is a cross-sectional view of a polymer yarn containing a single core. [Diagram 2] FIG. 2 is another cross-sectional view of multiple polymer yarns that include a single core with various characteristics. [Diagram 3] FIG. 3 is a diagram of a foam structure. [Figure 4] FIG. 4 shows a system for producing mono-yarn strands by extrusion process. [Diagram 5] FIG. 5 is a schematic diagram of the manufacturing process of the nonwoven yarn. [Figure 6]FIG. 6A is a perspective view of a portion of a yarn bundle, the yarns being in an untwisted configuration, FIG. 6B is a perspective view of the yarn bundle in a twisted configuration, and FIG. 6C is an enlarged view of a portion of the yarn bundle in a helical twist configuration. [Figure 7A] FIG. 7A is the first step in a sequence for producing a pitch and tension controlled twisted yarn. [Figure 7B] FIG. 7B is the second step in the sequence for producing pitch and tension controlled twisted yarn. [Figure 7C] FIG. 7C is the third step in the sequence for producing pitch and tension controlled twisted yarn. [Figure 7D] FIG. 7D is the fourth step in the sequence for producing pitch and tension controlled twisted yarn. [Figure 7E] FIG. 7E is the fifth step in the sequence for producing pitch and tension controlled twisted yarn. [Figure 8A] FIG. 8A is a top plan view of a knitted yarn structure. [Figure 8B] FIG. 8B is a top plan view of another knitted yarn structure. [Figure 8C] FIG. 8C is a top plan view of yet another knitted yarn structure. [Figure 8D] FIG. 8D is a top plan view of yet another knitted yarn structure. [Figure 8E] FIG. 8E is a top plan view of another knitted yarn structure. [Figure 8F] FIG. 8F is a top plan view of yet another knitted structure. [Figure 8G] FIG. 8G is a top plan view of yet another knitted structure. [Figure 9] FIG. 9 is a top plan view of the woven yarn structure. [Figure 10]FIG. 10A is a top view of the braided yarn before foaming, FIG. 10B is an enlarged top view of the braided yarn before foaming, and FIG. 10C is a top view of the braided yarn after foaming. [Figure 11A] FIG. 11A shows the first step in the Kumihimo braiding sequence. [Figure 11B] FIG. 11B shows the second step in the braid weaving sequence. [Figure 11C] FIG. 11C is the third step in the braid weaving sequence. [Figure 11D] FIG. 11D shows the fourth step in the braid weaving sequence. [Figure 11E] FIG. 11E is the fifth step in the braid weaving sequence. [Figure 11F] FIG. 11F is the sixth step in the braid weaving sequence. [Figure 12A] FIG. 12A is a top plan view of the knot. [Figure 12B] FIG. 12B is a top plan view of another knot. [Figure 12C] FIG. 12C is a top plan view of yet another alternative knot. [Figure 12D] FIG. 12D is a top plan view of yet another alternative knot. [Figure 13] FIG. 13 shows the principle process for producing anisotropic foam from polymer yarns. [Figure 14] FIG. 14 is a cross-sectional view of the polymer yarn of FIG. 1 in a foamed state. [Figure 15A] FIG. 15A is a perspective view of a cobra knot structure formed from polyamide 6 filaments prior to the foaming process. [Figure 15B] FIG. 15B is a perspective view of a cobra knot structure formed from polyamide 6 filaments after the foaming process. [Figure 16] FIG. 16 is a flow chart illustrating an exemplary foaming process for a yarn structure. [Figure 17] FIG. 17 is a perspective view of a high pressure reactor. [Figure 18A] FIG. 18A is a perspective view of a braided yarn structure. [Figure 18B] FIG. 18B is a perspective view of a foamed braided yarn structure. [Figure 19A] FIG. 19A is a perspective view of a braided yarn structure foamed at 108° C. [Figure 19B] FIG. 19B is a perspective view of a braided yarn structure foamed at 109° C. [Figure 19C] FIG. 19C is a perspective view of a braided yarn structure foamed at 110° C. [Figure 19D] FIG. 19D is a perspective view of a braided yarn structure foamed at 112° C. [Figure 20A] FIG. 20A is a perspective view of a twisted yarn structure. [Figure 20B] FIG. 20B is a perspective view of a foamed twisted yarn structure. [Figure 21A] FIG. 21A is a perspective view of a twisted yarn structure that was immersed at 103° C. and foamed at 34.5 MPa and 110° C. [Figure 21B] FIG. 21B is a perspective view of a twisted yarn structure soaked at 102° C. and foamed at 34.5 MPa and 108° C. [Figure 21C] FIG. 21C is a perspective view of a twisted yarn structure soaked at 103° C. and foamed at 20.7 MPa and 108° C. [Figure 21D] FIG. 21D is a perspective view of a twisted yarn structure soaked at 102° C. and foamed at 20.7 MPa and 108° C. [Figure 22] FIG. 22 is a schematic diagram of the apparatus for measuring circumferential shear strain. [Diagram 23] FIG. 23 is a bottom and medial perspective view of an article of footwear configured as a right shoe including upper and sole structure, the sole structure including anisotropic foam. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] The following description and accompanying drawings disclose various embodiments or configurations of midsoles with various thread structures. Although the embodiments are disclosed with respect to sports shoes, such as running shoes, tennis shoes, basketball shoes, etc., the concepts related to the shoe embodiments may be applied 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 shoe concepts may also be applied to non-athletic considered footwear products, including dress shoes, sandals, loafers, slippers, and high heels.

[0029] The term "about" as used herein refers to, for example, typical measuring and manufacturing procedures used for footwear or other products that may include embodiments disclosed herein, and variations in numerical quantities that may occur through inadvertent errors in those procedures, differences in manufacture, source, or purity of materials used to make a composition or mixture or to carry out a method, etc. Throughout this disclosure, the terms "about" and "approximately" refer to a range of values ​​of ±5% of the numerical value preceding the term.

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

[0031] The midsole may be a single polymeric material or may be a blend of materials such as EVA copolymer, thermoplastic polyurethane (TPU), polyester block amide (PEBA) copolymer, and / or olefin block copolymer. Additionally, the midsole may be heated using a supercritical gas such as CO2, N2, or mixtures thereof, for example, to heat the midsole. The midsole may be formed by a supercritical foaming process, such as, for example, physical foaming, chemical foaming, or the like, in which a material such as a teflon, TPE, or a mixture thereof is foamed. In such an embodiment, the midsole may be formed by a supercritical foaming process, such as, for example, physical foaming, chemical foaming, or the like, in an autoclave, an injection molding apparatus, or the like. The composite material may be manufactured using a process carried out in any sufficiently heated / pressurized vessel capable of processing the mixture of a boundary fluid (e.g., CO2, N2, or mixtures thereof) and a polymeric material (e.g., TPU, EVA, polyolefin elastomer, or mixtures thereof).

[0032] As used herein, the term "yarn," "fiber," or "filament" refers to a material that is The terms are used interchangeably and refer to an elongated piece of material. FIG. 1 shows a cross-sectional view of a yarn 100 that includes a single core 104. A yarn 100 that includes a single core 104 is called a monofilament. A monoyarn 108 is generally comprised of a single material. In some embodiments, the monoyarn 108 may be formed from a polymeric material such as polyester, polyethylene terephthalate (PET), polyethersulfone (PES), etc. However, a monoyarn 108 may be formed that comprises one or more different materials.

[0033] FIG. 2 illustrates another cross-sectional view of multiple polymer yarns 200 including polymer yarns 202 having various characteristics. 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 formed from any one or combination of polymers and / or any other suitable materials, such as, but not limited to, thermoplastic polyurethane (TPU), thermoplastic elastomer (TPE), thermoplastic copolyester (TPC), and polyamide (nylon).

[0034] In some embodiments, the multiple polymer yarn 200 may be formed from polymer yarns 202 having the same diameter, or the multiple polymer yarn 200 may be formed from one or more polymer yarns 202 having different diameters. In some embodiments, the multiple polymer yarn 200 may be formed from polymer yarns 202 of the same or different tear strengths. In some embodiments, the multiple polymer yarn 200 may be formed from polymer yarns 202 of the same or different denier, i.e., density of a single strand of yarn. In some implementations, the multiple polymer yarn 200 may be formed from polymer yarns 202 of the same or different denier, i.e., density of a single strand of yarn. In some configurations, multiple polymer yarns 200 may be coated with different substances or materials, and the thickness of the coating may vary among the polymer yarns 202. Multiple polymer yarns 200 may be formed from polymer yarns of the same or different colors. In some embodiments, multiple polymer yarns 200 may include polymer yarns 202 of various characteristics, such as, but not limited to, materials, diameters, tear strengths, denier, coatings, and colors.

[0035] A polymer is a substance or material that consists of repeating chains of monomers, such as homopolymers or copolymers. Natural polymers include silk, wool, rubber, cellulose, Naturally occurring materials such as polymers, cellulose, and proteins. Synthetic polymers are derived from petroleum and manufactured artificially. Synthetic polymers are classified into four different groups such as thermoplastic polymers, thermoset polymers, elastomers, and synthetic fibers.

[0036] Under applied heat, thermoplastic polymers can be either amorphous or crystalline. Thermoplastic polymers become pliable at high temperatures and harden upon cooling. For example, FIG. 1 shows a cross-section of a yarn 100 that includes a thermoplastic polymer core 112.

[0037] The thermoplastic polymer core 112 can include 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 can include from about 5 weight percent of the composition to about 100 weight percent of the composition of thermoplastic polymer, based on the total weight of the thermoplastic polymer.

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

[0039] Also, an elastomer is a type of polymer that has viscoelastic properties. In general, an elastomer can return to its original shape after being stretched or deformed. A yarn that includes an elastomeric core can provide, among other things, flexibility, strain resistance, and bias and / or spring-like properties. Elastomeric yarns can include, for example, elastene, such as Lycra®, or nylon or polyamide materials.

[0040] Referring to Figure 3, a foam blank 300 is an object formed by trapping pockets of a gas or gas mixture in a liquid or solid. The foam blank 300 includes a plurality of void structures 304 and The cell structures include a plurality of cell structures connected by a plurality of cell walls 312. The plurality of cell structures may be made of closed-cell foam 316 or It may be an open-cell foam 320. Closed-cell foam 316 is formed when individual gas pockets are completely surrounded by a solid material. 320 is formed when the gas pockets interconnect with one another. For example, the foam blank 300 can be formed from different polymers, such as thermoplastic and thermoset polymers. For example, the foam blank 300 has favorable properties such as light weight, 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 comprising a polymeric material. FIG. 4 illustrates the extrusion of polymer pellets 408 having identical material properties to form a thermoplastic polymer core. 4 shows a system 400 for forming a single strand of polymer yarn 404 comprising at least one polymer core, such as a thermoplastic polymer core. The strand of polymer yarn 404 can include 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 an inner wall 422 of the extruder 420 by a rotating screw 424 therein and melted by heaters 428 disposed along the extruder 420 to produce a molten polymer. The molten polymer exits the screw 424 and travels through a breaker plate assembly 432 that includes 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 extrudate 440. The polymer threads 404 in the extrudate 440 are then cooled in a cooling trough (not shown). In some examples, composite polymer threads may be produced by combining and extruding polymer pellets 408 of different material properties.

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

[0043] The yarn structure may be a two-dimensional yarn structure or a three-dimensional yarn structure based on the structural organization and intertwining of the yarn structure. Two-dimensional yarn structures do not extend in more than one direction. Two-dimensional yarn structures include, but are not limited to, non-woven yarns, woven yarns, braided yarns, laced yarns, which extend along a plane. Three-dimensional yarn structures include three-dimensional structures, including 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. 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] FIG. 5 illustrates a melt blowing process 500 for producing nonwoven yarn 504. The melt blowing process 500 blows raw material into a web structure 500. 8. The first step 510 involves feeding a low viscosity feedstock (not shown) into a hopper 512 where it is melted and extruded through an extruder 516 similar to extruder 420 of FIG. 4. The second step 518 involves feeding the feedstock through a feeding die hole in a spinneret 524. The method includes forming an extruded filament 520 from molten feedstock passing through a die 534 through a die hole 522. In a third step 526, the extruded filament 520 is directed toward a die 534 by primary air streams 528. The primary air stream 528 is blown at a high velocity and temperature to extrude the extruded filament 520 emerging from the spinneret 524 quickly and without cooling. The temperature of the primary air stream 528 can be measured by a thermocouple (not shown), and the temperature of the primary air stream 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 air stream 528 converge in a die 534 to form a fiber stream 532 and exit through an outlet 535 of the die 534. In a fourth step 530, a secondary air stream 536 having a lower temperature relative to the primary air stream 528 is applied to the fiber stream 532 to form a plurality of fibers 538. The secondary air stream 536 can be generated from ambient air and can be applied in a turbulent manner. In a fifth step 540, the plurality of fibers 538 are received by a receiving side 542 of a collector or netting machine 544. A die-collector distance 546 is defined between the exit of the die 534 and the receiving side 542 of the collector 544. The collector 544 is disposed downstream of the exit 535 of the die 534. For example, the collector 544 may be provided as a roller, such as a calender roller or a rotating drum. The collector 544 forms a web structure 508 by distributing and / or spreading the plurality of fibers 538 along the collector 544. In a sixth step 548, the web structure 508 is transferred onto a winding machine 550 that winds the web structure 508 to form the nonwoven yarn 504. The web structure 508 is then transferred onto a winding machine 550 that winds the web structure 508 to form the nonwoven yarn 504. The structure includes a die side 552 that is the exterior of the web structure 508 and a collector side 554 that is the interior of the web structure 508. For example, the properties of the web structure 508 may include polymer melt temperature, polymer throughput rate, primary The meltblowing process 500 is controlled by the selection and combination of several process variables, such as the primary air temperature, the primary air flow rate, and the web-collector distance. The aforementioned process variables determine the morphology and shape, e.g., diameter, of the fibers 538 that form the nonwoven yarn 504. For example, increasing the die-collector distance 546 allows the fibers 538 to have a greater length to become entangled by exposure to the secondary air flow 536, which results in increased fiber entanglement to provide a thicker, softer web structure. Additionally, the die-collector distance 546 can be increased to avoid fiber laydown irregularities, such as bunching or chunking, as the fibers 538 are entangled and collected. Increasing the die-collector distance 546 also improves fiber cooling by increasing the duration that the plurality of fibers 538 are exposed to the ambient air and / or secondary air flow 536. In contrast, the die-collector distance 546 generally results in less fiber entanglement, increased stiffness of the web structure, and improved barrier properties of the web structure.

[0045] 6A-6C, and with particular reference to FIG. 6A, a bundled yarn 600 may be formed from multiple yarns 604 arranged along a central axis CA. The multiple yarns 604 may include different material properties as described above and herein. FIG. 6B shows multiple yarns 604 twisted in a counterclockwise direction 606 to form a twisted yarn structure 608. A counterclockwise twisted twisted yarn structure 608 is known as an S-twist yarn. In some embodiments, the multiple yarns 604 may be twisted in a clockwise direction forming a Z-twist yarn. The twisted yarn structure 608 may be provided in various configurations and may take alternative forms other than those shown herein. For example, two or more twisted yarns of the single yarn 108 shown in FIG. 1 including a single thermoplastic polymer core may be bundled to form a bundled yarn 600 of multiple yarns 604. Specifically, referring to FIGURE 6C, the plurality of yarns 604 are twisted under axial tension applied along a central axis CA that is centrally located within the plurality of yarns 604 and extends along the length of the twisted yarn structure 608 through opposing ends thereof. The plurality of yarns 604 are twisted in either a clockwise or counterclockwise direction such that each yarn 614 of the plurality of yarns 604 is twisted along the central axis CA as shown in FIGURE 6C. 6. Define a helical axis HA disposed at a helical angle 612 relative to the Each yarn 614 forms a helix structure 616 defined by a helix angle 612. 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 instances about 45 degrees. Each yarn 614 may have a helix angle 612 that is uniform or may have one or more helix angles 612 that are different from each other. A solvent or blowing agent is impregnated into the twisted yarn structure 608 to form a multi-cellular foam structure, and the orientation of the cell growth direction provides anisotropic properties to the foam structure with respect to the central axis CA and the longitudinal direction. The foam 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 to the longitudinal direction of the central axis CA. In some embodiments, there are multiple cell growth directions that are different from each other, such as, 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 in the various intertwinings of the yarn structure provide unique anisotropy.

[0046] 7A-7E, a method 700 for twisting a yarn structure under controlled rotation and controlled tension is disclosed. In particular, with reference to FIG. 7A, a first stiff wire 704 and a second stiff wire 706 are used to hold a bundle of yarns 708 at each end. The bundle of yarns 708 is depicted in a simplified manner for purposes of illustration, but it will be understood that it may be configured in a variety of forms and shapes. With reference to FIG. 7B, the yarn bundle 708 is disposed within a tubular reservoir 712. The tubular reservoir 712 is then filled with water. 7C, both ends of the tubular reservoir 712 are configured to receive a septum or plug 716. A first septum 718 includes an opening 720 that allows the first rigid wire 704 to pass through to form a loop on the outside of the tubular reservoir 712. A second septum 722 includes a larger opening 724 to accommodate a small cut test tube 726 and a second septum 724 to accommodate a small cut test tube 726. The two rigid wires 706 pass through a small cut test tube 726. The second rigid wire 706 defines a fixed end 728, and the first rigid 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. With reference to FIG. 7D, with the weight 734 attached, the yarn bundle 708 is twisted under controlled rotation and tension. With reference to FIG. 7E, after the yarn bundle 708 is twisted to the desired degree (which may be measured in radians or units of degrees), the weight 734 is removed and the bundle of twisted yarns 738 is covered by aluminum foil 742, which is shown translucent for illustrative purposes. A solvent 744, such as styrene, is injected through the small cut test tube 726 into the tubular reservoir 712 to saturate and coat the bundle of twisted yarns 738. The tubular reservoir 712 containing the solvent 744 and twisted yarn 738 is then placed into an autoclave or reactor 746 to initiate the foaming process, which includes the controlled application of temperature and pressure, such as exposure to elevated temperature and pressure for a predetermined period of time in one or more cycles. A foam blank 752 is formed by depressurization by releasing pressure through a control valve 756.

[0047] In some embodiments, yarns may be knitted to manipulate the yarn structure. Knitted yarn structures can be formed by interlocking yarns to form loops, and thus knitted yarn structures can be provided in a variety of configurations. The knitting process intertwines the yarns so that they run parallel to one another. The knitting process can be modified, for example, to change the direction of loop formation, density of loop formation, and loop shape, among other aspects. Figures 8A-G show stitch structures for a knitted yarn structure 800. Figure 8A shows a rib stitch 804. Figure 8B shows a purl stitch 808. Figure 8C shows a welt stitch 812. Figure 8D shows an interlock stitch 816. FIG. 8E shows a tuck stitch 820. FIG. 8F shows a plain stitch 824. Thus, different stitching configurations, combinations, and materials can be used in different stitches. The coating can be applied in successive layers to impart different properties to each layer.

[0048] Generally, weft knitting 828 and warp knitting 832 are the two main methods by which yarn can be presented to needles to form a knitted yarn structure. As shown in FIG. 8F, the weft knitting method 828 is accomplished by forming multiple loops 836 using needles (not shown) along a horizontal direction HD. In the weft knitting method 828, multiple loops 836 are formed from a single common yarn along the horizontal direction HD and using specific needling patterns. The weft knitting method 828 can be accomplished using a circular knitting machine or a flatbed machine. Referring to FIG. 8E, the warp knitting method 832 is accomplished by forming loops in a vertical direction VD. The yarns interlock vertically along the vertical direction VD, and a plurality of loops 836 are formed from a combination of several separate yarns that are longitudinally disposed along the vertical direction VD and oriented parallel to one another. The warp knitting method 832 can be accomplished using a raschel machine. It is possible.

[0049] In some embodiments, referring to FIG. 8G, a spacer knit 84 4 can be used to create an ultra-lightweight yarn structure. Spacer knit 844 comprises a first substrate layer 848 and a second substrate layer 852. First substrate layer 848 and second substrate layer 852 are woven together with a plurality of weft yarns and / or woven layers 854 to form surface 854. or warp yarn structure. A plurality of spacer yarns 856 9 , which are disposed perpendicularly along a longitudinal axis VA between the first substrate layer 848 and the second substrate layer 852 to form a plurality of air traps 858. The faces 854 of the first substrate layer 848 and / or the second substrate layer 852 may be woven into various configurations, such as, for example, a hexagonal mesh or a chain mesh, to manipulate the orientation of the plurality of spacer yarns 856 along the weft direction (shown in FIG. 9 ) or the warp direction (shown in FIG. 9 ). The orientation relative to the longitudinal axis VA may be manipulated to vary the shrinkage strain of the plurality of spacer yarns 856.

[0050] 9, single yarns 108 (see FIG. 1) or multiple polymer yarns 200 (see FIG. 2) can be woven to form a woven yarn structure 900. The woven yarn structure 900 may be provided in a variety of configurations and may take other forms than those shown and described herein. The yarns arranged in the horizontal direction HD or weft direction WED are referred to as weft yarns 902. The yarns arranged in the vertical direction VD or warp direction WAD are referred to as weft yarns 903. The yarns arranged in the vertical direction VD or warp direction WAD are referred to as weft yarns 904. The yarns are called warp yarns 904. The periphery of the warp yarns 904 that creates the edge 908 of the fabric. The weft yarns 902 wrapped around the weft are referred to as selvedges 912. In some embodiments, the weaving method includes two separate sets of yarns that are interwoven perpendicularly to form the woven yarn structure 900. Thus, the two separate sets of yarns are interwoven to create a plain weave structure, a satin weave structure, or a twill weave structure. In this manner, Thus, the weaving process orients the yarns in a vertical crisscross pattern 916, allowing the woven yarn structure 900 to maintain a thin profile, but also limiting the stretchability of the woven yarn structure 900.

[0051] In some embodiments, the yarns are woven on a weaving machine, such as, for example, a shuttle type, a circular type, or a narrow type. (not shown). Shuttle looms are generally electronically controlled and configured to weave tight warp and weft patterns. Shuttle type looms have a narrow piece of wood or plastic with notches at the ends to hold the threads, and they move automatically back and forth between the vertical warp threads and weave through the horizontal weft threads. Conventional circular type looms A loom is a machine that consists of two or more shuttles that move simultaneously in a circle to weave a weft thread onto a portion of the warp threads, and is generally electronically controlled. Electronic looms can take on various mechanisms, but the basic principle for creating a woven structure is the same. Non-electrical, hand-operated machines can be used for weaving, such as a loom. A loom is a device that weaves by applying tension to the warp threads to facilitate the weaving of the weft threads. The orientation or shape of various looms can vary, but the basic function is the same.

[0052] In some embodiments, the knitted yarn structure 800 of Figures 8A-8G or the woven yarn structure 900 of Figure 9 can have different properties by using different materials, different yarn thicknesses, or different colors, such as yarn count, twist in yarn, yarn strength, torsional properties, elongation, elasticity, tear strength, and bending properties. Some examples include:

[0053] 10A-C, multiple strands of yarn can be braided to form a braided yarn structure 1000. With reference to FIG. 10A, the braided yarn structure 1000 may be provided in a variety of configurations and may take other forms than those shown herein. The braided yarn structure 1000 is comprised of a first yarn 1004, a second yarn 1008, and a third yarn 1012. With reference to FIG. 10B, the first yarn 1004 passes over the second yarn 1008 and under the third yarn 1012. The third yarn 1012 passes over an adjacent yarn. In the illustrated embodiment, the first yarn 1004 passes under the second yarn 1008. The yarns 1004, 1008, 1012 are braided continuously along a central axis CA, which allows the braided yarn structure 1000 to distribute tensile loads more evenly. The braid is defined by a braid 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 intertwining of the continuous yarn structure. Referring to FIG. 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 involves foaming the continuous yarn structure 1020 under supercritical conditions. Allows for diffusion and solubilization of CO2 molecules within the woven yarn structure material under supercritical conditions, as well as the generation of CO2 bubbles within the material. It is caused by sudden decompression.

[0054] In some embodiments, the two-dimensional braided structure comprises axial yarns aligned along the axial load direction and braider yarns at an angle to the axial yarns to form various braided structures. The two-dimensional braided structure may be straight, product curved, or a plane shell. Regular braids include, but are not limited to, Different braided structures such as regular braid, diamond braid, and Hercules braid are fabricated with different braided angles 1016. The diagonal weave 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 weave angles 1016 fall between 30 degrees and 80 degrees from the central axis CA. The central axis CA is the orientation along 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. Thus, the braided structure 1000 of FIG. 10 may be used to weave yarns together to form a circular braid, according to known methods. At the same time, a braided structure may be manufactured using the circular braid while maintaining all braided yarns under axial tension. In some embodiments, the axial tension may be altered or varied, or the axial tension may be maintained at a constant level, for a period of time, or throughout the entire process. Relatively, For short lengths of hand knitted yarn, individual weights can be used to tension and / or adjust the yarn by adding or removing weights as desired. In some embodiments, the yarn is placed around a core or mandrel and braided in a straight line, e.g., from top to bottom. This hand knitting method is known as maypole braiding, and the principle can be used for over-braiding of different construction profiles. It is used.

[0056] 11A-F, a braided cord 1100 may be used to form a tubular braid. The braided cord 1100 utilizes a braiding machine 1104 manufactured from a tough, dense foam having multiple notches 1106 around its periphery 1108 that allow for the creation of the necessary tension in the braiding threads. The braiding machine 1104 is typically manufactured in a disk shape that allows for the braiding of tubular braid profiles, although the braiding machine 1104 may be rectangular or square, which provides the braiding ability to create flat braids.

[0057] With reference to FIG. 11A, eight strands of yarn may be tied together by a knot at one end or a bobbin (not shown) may be used to hold the yarns together and prevent tangling. In some embodiments, the braid (not shown) may be tied into a knot to tension the yarn in a direction perpendicular to the horizontal axis HA defined by the braiding machine 1104. With reference to FIG. 11B, in the braid weaving 1100, a first yarn 1110, a second yarn 1112, a third yarn 1114, a fourth yarn 1116, a fifth yarn 1118, a sixth yarn 1120, a seventh yarn 1122, and an eighth yarn 1124 are positioned within a number of notches 1106 around a periphery 1108 referred to as warp yarns 1128. The braiding machine 1104 of the present disclosure includes 32 notches and eight strands of yarn. A knot 1132 is placed in a central cavity 1136 on the braiding machine 1104, and the eight strands are divided into four subgroups, each having two strands. For example, a first subgroup 1140 includes a first yarn 1110 and a second yarn 1112, a second subgroup 1144 includes a third yarn 1114 and a fourth yarn 1116, a third subgroup 1148 includes a fifth yarn 1118 and a sixth yarn 1120, and a fourth subgroup 1152 includes a seventh yarn 1122 and an eighth yarn 1124. The first subgroup 1140 is held by a notch 1106 located at a first position 1160 adjacent to a first dot 1162, the second subgroup 1144 is held by a notch 1106 located at a second position 1164 adjacent to a second dot 1166, the third subgroup 1148 is held by a notch 1106 located at a third position 1168 adjacent to a third dot 1170, and the fourth subgroup 1152 is held by a notch 1106 located at a fourth position 1172 adjacent to a fourth dot 1174. For example, the first subgroup 1140, including the first yarn 1110 and the second yarn 1112 at the first position 1160, is held in a notch adjacent to the first dot 1162. The first yarn 1110 is held in a notch located to the left of the first dot 1162, and the second yarn 1112 is held in a notch located to the right of the first dot 1162.11C, with the first dot 1162 facing up and the third dot 1170 facing down, 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 located to the left of the first dot 1162. Referring to FIG. 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 FIG. 11E, the braiding disk 1104 is rotated a quarter turn clockwise, causing the fourth dot 1174 to face up and the second dot 1166 to face down. The braiding process of Figures 11C and 11D is repeated by moving the lower left most yarn across the horizontal axis and placing it adjacent to the upper left most yarn, and moving the upper right most yarn across the horizontal axis and placing it adjacent to the lower right most yarn to form the braided structure 1000 of Figure 10 along the product axis. The product axis PA extends perpendicular to the braiding disk 1104. Referring to Figure 11F, the braiding disk 1104 is again rotated a quarter turn in the clockwise direction and the braiding process of Figures 11C and 11D is repeated.

[0058] In some embodiments, the braided profile is a horn gear abutment. Braiding machines can be used to make braided profiles, including but not limited to horn gear braiders, maypole braiders, square braiders, Wardwell rapid braiders, and high speed programmable logic controller braiders. A typical process for a braiding machine begins with the yarn being wound onto a bobbin, the bobbin being attached to a carrier, and the carrier being attached to the braiding machine to produce the braided profile.

[0059] In some embodiments, the braided profile may include different properties such as, but not limited to, different materials, thicknesses, and colors. Materials may have different frictional properties, flexural properties, tensile properties, torsional properties, moduli of elasticity, elongation at break, etc. The first and second yarns may include different polymer cores having different mechanical properties such as extensions, plasticity, elastic limits, breaking points, and elongation. For example, three plied yarns including various properties may be used to form the braided yarn structure 1000. The first yarn may have a thicker diameter than the second and / or third yarn. The second yarn includes a different material compared to the first and / or third yarn. The third yarn includes the same type of material as the first yarn but has a different diameter. Thus, various yarns may be braided to create a yarn profile based on the application of the braided yarn structure 1000.

[0060] 12A-D, sections of yarn, such as twisted yarn structure 608, knitted yarn structure 800, and braided yarn structure 1000, can be stretched by securing adjacent sections of yarn with a knot 1200. Knot 1200 can include any of a variety of well-known knot configurations, including a double fisherman's knot, an Eskimo bowline knot, a double figure eight knot, a fisherman's knot, a half hitch knot, a Calmy Croop knot, an overhand knot, an overhand loop knot, a reef knot, a thief's knot, a square knot, a plafond knot, and a friendship knot. In some embodiments, the outer layer of knot 1200 may be heat pressed at a particular temperature and / or pressure to maintain the shape permanently or semi-permanently.

[0061] As used herein, the terms "foaming agent", "solvent", "pneumatogen" or "blowing agent" are used interchangeably and refer to a substance capable of producing a cellular structure during the foaming process. Foaming agents are classified as physical blowing agents, chemical blowing agents, or both. agent, or mixed physical-chemical blowing agent. Examples include, but are not limited to, the following:

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

[0063] The blowing agent compound may include 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 include blowing agents with different properties, such as, for example, activation temperature. That is, the blowing agent compound temperature may be determined by the amount of the blowing agent that is present. The activation temperature of the blowing agent may be defined as the average of the different activation temperatures of the blowing agents contained in the composition. The average may be calculated on a per unit mass or per unit volume basis. The activation temperature ranges of the blowing agents may differ from each other, for example, by about 5°C, or about 10°C, or about 30°C. In this way, foam structures with unique properties can be achieved by selection of a blowing agent with a specific activation temperature. Physical and chemical blowing agents can be combined together so that the compound balances each other in terms of 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 when 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, the foaming agent may be sufficient to expand the volume of the sample from the initial volume to a final volume. The final volume may be about 10 percent or more, about 20 percent or more, about 30 percent or more, about 50 percent or more, about 100 percent or more, or about 300 percent or more of the initial volume before foaming.

[0065] In thermoplastic foaming, it is important to obtain a foam with 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 inhibited, resulting in insufficient cell growth being formed in the foam blank.

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

[0067] The foam blank provides favorable properties within the midsole by increasing hardness, water resistance, rigidity, cushioning, sound dampening, impact dampening, etc. Commonly known foam materials have a convex cell shape and exhibit a positive Poisson's ratio, defined as the negative value of the lateral strain divided by the axial strain when loaded axially. Materials containing foams contract laterally in response to axial stretching and expand laterally in response to axial compression, resulting in a positive Poisson's ratio. Poisson's ratios range from 0.1 to 0.4 for typical polymer foams. For example, foams undergo permanent property and material property changes when the foam is placed under tension at elevated temperatures. Depending on the direction of tension, unidirectional or bidirectional anisotropic foams can be formed.

[0068] Typically, foam 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 allow foams to be formed with equal behavior and material properties in the same direction, and the Poisson's ratio in three dimensions is about -1.0 to 0.5. The benefits of the foam multi-cell yarn structure can be further exploited by pre-orienting the cell structure. A foam structure or foam material whose properties depend on the orientation in which they are measured is described as anisotropic. Anisotropy is defined as the tendency of a material to respond differently to stresses 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 (noted as the shape anisotropy ratio R). The anisotropy ratio of a typical foam is about 1.3, and the ratio typically varies between about 1 and about 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 anisotropy ratio along the maximum and minimum cell dimensions is The ratio of the Young's moduli provides the anisotropy ratio R.

[0069] The anisotropic behavior of the foam structure may be introduced by the release of confinement in one or more directions. Methods to increase the anisotropic ratio of polymer foams include through a mold, through a multiphase structure with various components, or through the addition of fibers or filaments along the cell rise direction. The process of increasing the anisotropic ratio of polymer foams can be deduced 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 with complex three-dimensional foam structures that can be tailored during the solidification process. Freeze-casting techniques offer various advantages, such as the volumetric dimensions, shape, and orientation of the cell structures that can be tailored by varying the suspension characteristics (e.g., liquid type, additives, particulate fraction, etc.) and solidification characteristics (e.g., speed, temperature, orientation, external force field, etc.). Various solidification methods, such as unidirectional, bidirectional, radial, radial central, and dynamic freezing methods, have been investigated as a means to control the porosity and microstructure for the freezing process.

[0071] FIG. 13 shows a thermoplastic polymer yarn specimen 130. FIG. 13 shows a process 1300 for foaming a yarn sample 1304. The process 1300 involves polymer saturation or impregnation of a yarn sample 1304 with a foaming agent 1308. The foaming agent 1308 may be a physical foaming agent, a chemical foaming agent, or a mixture of physical and chemical foaming agents. The process 1300 involves the formation of a supersaturated polymer-blowing agent mixture, which may be induced by increasing the temperature and pressure above critical values. 13. Additionally, the process 1300 includes cell nucleation or cell growth 1320 of the thermoplastic yarn sample 1304 through a sudden pressure reduction 1324, depicted as a cloud-like diagram, by the operation of a valve 1328, as represented by the expansion of the exemplary yarn sample 1304 in FIG. 13. Additionally, the process 1300 includes cell stabilization, where pressure and temperature are brought to ambient pressure and temperature to form a foam structure 1332. The well-known batch foaming is applied in two different ways, including a pressure-induced method and a temperature-induced method. In the pressure-induced method, as shown in FIG. 13, a first step 1350 includes a yarn sample 1304 being saturated with a foaming agent 1308. The second step 1354 involves cell nucleation 1320 of the yarn sample 1304 induced by the foaming agent 1308 via a sudden depressurization 1324 caused by the operation of a valve 1328. The sudden depressurization 1324 of the system to ambient atmospheric pressure initiates the foaming process to produce a foam 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 ambient temperature for a period of time, which causes cell nucleation and growth. For example, but not limited to, the temperature of the oil bath can be maintained at a temperature between 80°C and 150°C. After the bubbles (cells) are generated, the foam structure 1332 is placed in a cooling bath in water or solvent.

[0073] As used herein, a supercritical fluid will be understood to be a substance whose temperature and pressure are above its critical point, no distinct liquid and gas phases exist, and the pressure is below that required to compress the substance into a solid. Supercritical fluids dissolve materials such as liquids and solids. Near the critical point, small changes in pressure or temperature can result in large changes in density. Carbon dioxide and water are the most 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, similar to organic solvents.

[0074] Furthermore, as used herein, a superheated fluid will be understood to be a substance in which the fluid is in equilibrium with the vapor at the saturated vapor pressure. For example, superheated water is a well-known superheated fluid. Superheated water is configured to be stabilized or metastable in an environment where the superpressure increases the boiling point and liquid water is in equilibrium with the vapor, which can be obtained by heating the water in a closed container with a head space. During the interaction of the superheated fluid or moisture with the foam structure, the relatively high temperature of the superheated fluid causes the gas trapped in the foam structure to expand and enlarge the voids, thereby decreasing the overall density of the foam structure. With respect to the supercritical state, a medium such as CO2 or N2 rises above its critical point and allows it to access small voids that are inaccessible below the critical point by diffusion into the foam structure, thereby partially making the density of the supercritical medium relatively high. Exposing the foam structure to a supercritical medium plasticizes a portion of the foam structure and saturates the foam structure. In a subsequent step, the foam structure is restricted to a supersaturated state, for example by reducing the pressure or increasing the temperature, to cause the nucleation and relative growth of porous cells within the polymer matrix of the foam structure. Exposure to the supercritical medium and supersaturation reduces the overall density of the foam structure. These properties make supercritical and superheated conditions, respectively, favorable conditions for carrying out extraction or impregnation processes, since the density can be continuously adjusted by varying the experimental conditions of temperature and pressure.

[0075] FIG. 14 shows a cross section of an expanded thermoplastic yarn 1400. A first inner diameter 1404 corresponds to the yarn 100 of FIG. 1 before undergoing the expansion process described herein, and a second outer diameter 1408 shows the yarn 100 of FIG. 1 after it has been expanded to form the expanded thermoplastic yarn 1400. When the yarn 100 interacts with a supercritical blowing agent such as CO2, the yarn 100 becomes saturated with the gas above the supercritical state. By reducing the pressure or increasing the temperature, the yarn 100 becomes supersaturated where porous cells grow within the polymer matrix. When the yarn 100 is under supercritical conditions, the melting point, heat-glass transition, crystallization temperature, crystallization rate, and expansion rate change. The expansion process changes the physical properties of the polymer, such as the wettability, and the ability to dissolve the polymer. Generally, the penetration of the solvent induces swelling by reorienting the polymer chains to form a thermodynamically favorable crystalline state. The expansion process increases the diameter and induces a diameter change, i.e., a change in the polymer thread 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 thread.

[0076] 15A-B, a knot structure, understood to be a cobra knot, formed from polyamide 6 monofilament 1504 was used to observe the change in diameter 1506 before and after foaming 1508 and foaming 1510 were generated. The polyamide 6 monofilament 1504 was treated with a superheated water and supercritical carbon dioxide to form a cobra knot structure 1500. The cobra knot structure 1500 formed with 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 a highly porous structure.

[0077] Methods for foaming a yarn structure are described below. The yarn structure may include any of the yarn materials, yarn characteristics, and foaming agents described above. Under supercritical conditions, impregnation of the foaming agent foams the material and forms at least one foamed region along the yarn structure. For example, any of the thermoplastic yarns may be Yarn structures incorporating either of these can be processed under supercritical conditions to create multi-cell foams containing multiple cavities. The cavities may include open-cell foam structures or closed-cell foam structures. The introduction of bubbles from a blowing agent induces the formation of the cellular structures during the manufacturing process. When foamed, the foamed multi-cellular yarn structures have different mechanical properties compared to non-foamed yarn structures. For example, the foamed structures can impart increased texture, strength, cushioning, abrasion resistance, and / or a combination of other material properties.

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

[0079] In some embodiments, the yarn structure includes unidirectional and / or bidirectional. The yarn structure including unidirectional and / or bidirectional may be pre-oriented in the foam blank to form a tunable 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, the first cell growth orientation being different from the second cell growth orientation. The anisotropic cell orientation provided by the various yarn structures described above allows the foam blank to have desirable characteristics at ideal locations. The various yarn structures and configurations described above provide a collapsing structure with flexibility in one or more specific directions, a rebound structure with elasticity in one or more specific directions, and a resilient structure with elasticity in one or more specific directions. ), and support structures with rigidity in one or more specific directions. Pre-orientation of the various yarn structures and yarn configurations allows specific regions of the foam to exhibit different technical, direction-dependent, and performance characteristics.

[0080] Referring to FIG. 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 within 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. The high-pressure reactor 1710 includes an internal chamber (not shown) configured to receive a yarn structure sample or portion thereof that can be infiltrated 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 regulate the specific temperature. The outlet valve 1704 may be a ball valve (not shown) for rapid depressurization of the reactor or may include a needle valve for slower depressurization.

[0081] The mechanism of microcellular structure may be different based on the formation method of twisted or braided yarn structure. In the present invention, the mechanism of microcellular structure of anisotropic polyamide filaments is investigated by analyzing the crystallinity, change in diameter after foaming, change in density after foaming, and / or change in cross-sectional area after foaming, as determined by differential scanning calorimetry. FIG. 18A shows a braided yarn structure 1800 formed by the braiding machine shown in FIG. 11 before foaming, and FIG. 18B shows an expanded braided yarn structure 1802. When the fiber 1804 comprising the braided yarn structure 1800 is pulled in tension, the fiber's crystallinity percentage and diameter change based on the strain induced by the tension. The crystallinity percentage can be determined by comparing the density of the sample to the amorphous density of the sample by using differential scanning calorimetry. Table 1 shows the relationship of the crystallinity percentage and the change in diameter to the strain.

[0082] Table 1: Percent crystallinity and diameter change versus strain induced by fibers pulled with a tensile force. [Table 1]

[0083] The braided yarn structure 1800 has a filament diameter of 0.56 mm and a fiber weight of approximately 1.22 g / cm 3First, the immersion step is performed by immersing the braided yarn structure in superheated water at a temperature in the range of about 101° C. to about 105° C. at a pressure in the range of about 20.7 MPa (megapascals) to about 34.5 MPa for about 4 hours. The foaming step involves immersing the foam body 1800 in water. Second, the foaming step is carried out at a temperature ranging from about 106°C to about 112°C and a pressure ranging from about 20.7 MPa to about 34.5 MPa. Foaming occurs via rapid decompression forming the foamed woven yarn structure 1802. The foamed woven yarn structure 1802 exhibits an increase in filament diameter from 0.56 mm to 1.57 mm, which is about a 180% increase in filament diameter size, and a foaming rate of 1.22 g / cm 3 from 0.332 g / cm 3 3. The foamed braided yarn structure 1802 thus exhibits a density change of about 60%. In some embodiments, the foamed braided yarn structure 1802 exhibits a density change of at least 45%, or at least 50%, or at least 60%, or more. It will be appreciated that the twisted yarn structure 608 can also exhibit a similar change by the techniques described herein, such that the twisted yarn structure 608 can exhibit a density change of at least 45%, or at least 50%, or at least 60%, or more. The foamed braided yarn structure 1802 also exhibits a bias applied to the braid by maintaining the twist it had prior to foaming. The increased fiber area, change in density, and porosity of the foamed braided yarn structure 1802 are shown based on foaming temperature.

[0084] Table 2: Woven foam samples [Table 2]

[0085] 19A-D show corresponding cross-sectional views of the above-mentioned woven structure foam samples 1-4.

[0086] 20A shows a twisted yarn structure 2000 formed using the method shown in FIGS. 7A to 7E. First, the immersion step is a step of immersing the twisted yarn structure 2000 in superheated water at a temperature in the range of about 101° C. to about 105° C. at an atmospheric pressure in the range of about 20.7 MPa (megapascals) to about 34.5 MPa for about 4 hours. Second, the foaming step is carried out at a temperature ranging from about 106° C. to about 112° C. and a pressure ranging from about 20.7 MPa to about 34.5 MPa. Referring to FIG. 20B, foaming occurs by rapid decompression forming foamed strand structure 2002. Table 3 shows the increase in fiber area, change in density, and porosity of foamed strand structure 2002 based on foaming temperature.

[0087] Table 3: Twisted structure foam samples [Table 3]

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

[0089] In the present invention, PA-PS (polyamide-polystyrene) composite samples were prepared using the technique shown in Figures 7A-7E to investigate the filament orientation with respect to the circumferential shear strain assembly. For example, the pitch at which the yarns are arranged may result in insufficient adhesion between the filaments of the woven structure during compression. Since the midsole of the footwear product is subjected to repeated compression, it is important to understand the relationship between the filament orientation and the compression. The filament sample contains 60 filaments having a length of about 6.2 cm to 6.6 cm, which are twisted for 2.5 to 4 full revolutions with a hanging mass of 1 kg. Styrene monomer, 0.3 mol% tert-butyl peroxybenzoate initiator, and methanol were used. A solvent is used to fabricate the PA-PS composite sample. First, the PA-PS composite sample is immersed at 75°C for 24 hours at 27.6 MPa. Second, PS polymerization occurs at 115°C for about 4 hours to 16 hours at 27.6 MPa. After polymerization occurs, the composite sample is rapidly depressurized to ambient temperature using an outlet valve 1704 (see Figure 17) in the form of a ball valve. The change in diameter of the PA-PS composite sample can be determined by observing the initial radial pitch (Pi) and final radial pitch (Pf), the initial height and the final height, and measuring the change in rotation. Table 4 shows the relationship between polymerization time, pitch of the fiber before swelling, pitch after swelling, and change in diameter.

[0090] Table 4: Polymerization tests [Table 4]

[0091] The increased filament diameter corresponds proportionally to the increased 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 proper foaming applications. The change in pitch, i.e., angle, of the filaments before and after swelling can be the result of a 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 pitch and the change in 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 revolutions per meter and a final radial pitch Pf of 59.4 revolutions per meter, which is a 56.7% increase in radial pitch, and a 122% diameter increase was also observed. In contrast, sample 3 was observed to have an initial pitch Pi of 37.9 revolutions per meter and a final radial pitch Pf of 60.5 revolutions per meter, which is a 59.6% increase in radial pitch, and a 135% diameter increase was also observed. The main difference between samples 1 and 3 is the polymerization time, with sample 3 having a polymerization time of 16 hours and sample 1 having a polymerization time of only 4 hours. It is therefore speculated that the longer polymerization time of the sample allows for a larger increase in radial pitch, which in turn may allow for a larger increase in diameter. It is understood that sample 4 had a polymerization time of 16 hours and underwent a foaming process, resulting in a diameter increase of 178%, significantly larger than the diameter increase of any of samples 1, 2, and 3.

[0092] 22 shows an apparatus 2200 that allows for the measurement of circumferential shear strain in compression. The apparatus 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, which in turn 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. The 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 thrust ball bearing 2210 limits rotation of the surfaces about the vertical axis VA except for the bearing 2210. The thrust ball bearing 2210 is the only surface that can rotate when subjected to a compressive force to measure the circumferential shear strain. The circumferential shear strain can be measured by multiplying the change in angle about 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 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 is equal to 0.13 as determined by Equation 1 above. In this way, the compression test can measure the circumferential shear strain during compression and provide a method to calculate the ideal pitch and / or diameter derived by using Equation 1.

[0095] The present disclosure relates to articles of footwear or specific components of articles of footwear, such as soles. FIG. 23 illustrates an exemplary embodiment of an article of footwear 2300 including 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 interior cavity 2312 into which a user's foot may 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, the midsole 2306 including the tunable foam 2310 can provide the benefits of a multi-component sole. Typically, prior art multi-component soles include separate components, such as plates, that are assembled together. In some examples, the plate is sandwiched between the upper and lower segments of the midsole. However, the present invention provides a sole structure 2304 to include anisotropic foam 2310 that achieves the desired functionality provided by a multi-component midsole, but does not require multi-component manufacturing and assembly. In other words, without adding the additional configurations or elements of a multi-component midsole, the midsole 2306 including the pre-oriented anisotropic foam 2310 of the present 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 vary in one or more tunable properties across the sole structure 2304. For example, the heel region 2318 may include a pre-oriented anisotropic foam having rebounding and shock absorbing properties. The midfoot region 2316 may include a secondary foam 2310 having greater flexibility, less stiffness, and / or energy return features. In some embodiments, the sole structure 2304 may be comprised of multiple anisotropic foams 2310 in the form of segments located 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 include pre-oriented anisotropic foams in the forefoot region 2314, the heel region 2318, the midfoot region 2316, or a combination thereof. The pre-oriented anisotropic foam 2310 is a single, unitary component that includes the pre-oriented anisotropic foam 2310. Thus, the pre-oriented anisotropic foam 2310 provides selective or tunable changes in properties and functionality to the midsole 2306, such as changes in stiffness or flexibility. The pre-oriented anisotropic foam 2310 may be pre-oriented using twisting or braiding techniques described herein.

[0098] As described herein, the multi-cell foam blanks including the polymer yarn structures may exhibit beneficial properties such as ease of manufacturing, minimal waste, and versatile design, among other benefits. Additionally, the pre-oriented anisotropic midsole may allow for good waste management and recycling of the material after the shoe is discarded. The sole structure 2304 including the midsole 2306, such as a single layer midsole, facilitates separation of the material allowing the thermoplastic to be melted into flakes and small pieces. Conventional shoe manufacturing techniques use various machines and chemicals to manufacture shoes. On average, a shoe includes numerous parts made from a variety of different materials that contribute to the production and / or retention of greenhouse gases, including carbon dioxide, in the atmosphere. Additionally, shoes formed by conventional manufacturing techniques and manufactured from multiple components are difficult to recycle due to the differences in the materials used, especially when those materials are glued together. As a result, approximately 80% of sneakers end up in landfills, where the shoes decompose over a long period of time, releasing toxins, chemicals, and fossil fuels into the surrounding environment. In the present invention, the sole structure is manufactured from anisotropic foam from polymer yarns to eliminate or reduce the use of multiple components in the sole structure. Thus, there is no need to disassemble the sole structure to remove embedded or attached components in order to reuse the shoe. Furthermore, the reduction in the number of components leads to a reduction in the pollution caused by the transportation and shipping 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 shoe and its components. In addition, the foaming process and the anisotropic foam can provide high stability, durability, and puncture resistance to extend the service life of the shoe. Furthermore, assembling multiple components typically involves the use of adhesives or cements, which may release toxins into the environment during various stages of use, such as during assembly or recycling.The present invention provides a single structure having less or no multiple components, which can reduce or eliminate the need to use adhesives and / or cements, thereby reducing their environmental impact.

[0099] Any of the embodiments described herein can be modified to include any of the structures or methods disclosed in connection with the various embodiments. Similarly, in some embodiments, materials or construction techniques other than those disclosed above can be substituted or added in accordance with known approaches. Furthermore, the disclosure is not limited to the types of footwear articles specifically shown. Furthermore, aspects of any of the footwear articles of the embodiments disclosed herein may be modified to function with any type of footwear, apparel, or other athletic equipment.

[0100] As previously mentioned, while the present disclosure has been described above with reference to specific embodiments and examples, it will be understood by those skilled in the art that the present disclosure is not necessarily so limited, and that numerous other embodiments, examples, uses, modifications, and departures from the embodiments are intended to be encompassed by the claims appended hereto.

Claims

1. selecting a plurality of yarns, at least two of the yarns having different properties from one another; bundling the plurality of yarns to form a bundled yarn structure; twisting the bundled yarn structure by fixing ends of the bundled yarn structure, applying axial tension to the bundled yarn structure, and rotating the bundled yarn structure to form a twisted yarn structure; depositing the stranded structure in a first mold in an autoclave; applying a supercritical fluid to the stranded yarn structure to allow the supercritical fluid to infiltrate and saturate the stranded yarn structure; depressurizing the autoclave to initiate a foaming process to convert the stranded yarn structure into an anisotropic foam blank; and depositing the anisotropic foam blank into a second mold configured as a midsole for an article of footwear.

2. The method of claim 1 , wherein at least one thread of the plurality of threads is comprised of at least one of a thermoplastic polymer, a thermoset polymer, or an elastomeric polymer.

3. The method of claim 1 , wherein the anisotropic foam blank includes a first cell growth direction parallel to a longitudinal direction of the stranded structure.

4. The method of claim 3 , wherein the anisotropic foam blank includes a second cell growth direction perpendicular to the longitudinal direction of the stranded structure.

5. The method of claim 1 , wherein the supercritical fluid comprises superheated water or supercritical carbon dioxide, or both.

6. The method of claim 1 , wherein the diameter of at least one thread of the plurality of threads increases by at least 120%.

7. The method of claim 1 , wherein the density of at least one of the plurality of yarns is reduced by at least 50%.

8. selecting a plurality of yarns, at least two of the yarns having different properties from one another; bundling the plurality of yarns to form a bundled yarn structure; applying axial tension to the bundled yarn structure and twisting the bundled yarn structure using a braiding technique to form a braided yarn structure; depositing the braided yarn structure in a first mold in an autoclave; applying a supercritical fluid to the woven yarn structure to cause the supercritical fluid to infiltrate and saturate the woven yarn structure; depressurizing the autoclave to initiate a foaming process to convert the braided yarn structure into an anisotropic foam blank; and depositing the anisotropic foam blank into a second mold configured as a midsole for an article of footwear.

9. The method of claim 8 , wherein at least one thread of the plurality of threads is comprised of at least one of a thermoplastic polymer, a thermoset polymer, or an elastomeric polymer.

10. The method of claim 8 , wherein the supercritical fluid comprises superheated water or supercritical carbon dioxide, or both.

11. 10. The method of claim 8, wherein the diameter of at least one thread of the plurality of threads increases by at least 120%.

12. The method of claim 8 , wherein the density of at least one of the plurality of yarns is reduced by at least 50%.

13. 9. The method of claim 8, wherein the plurality of yarns have a circumferential shear strain greater than 0.

05.

14. The method according to claim 8, wherein the braiding technique is a braid braiding technique.

15. an upper and a midsole having a forefoot region, a heel region, and a midfoot region; The article of footwear, wherein the midsole comprises pre-oriented anisotropic foam in at least one of the forefoot region, the heel region, or the midfoot region.

16. 16. The article of footwear of claim 15, wherein the pre-oriented anisotropic foam is provided in the form of separate segments including a forefoot segment, a heel segment, and a midfoot segment.

17. 16. The article of footwear of claim 15, wherein the midsole is a unitary structure having the pre-oriented anisotropic foam in each of the forefoot region, the heel region, and the midfoot region.

18. 16. The article of footwear of claim 15, wherein the midsole differs in at least one of flexibility or stiffness between the forefoot region, the heel region, and the midfoot region.

19. 20. The article of footwear of claim 18, wherein the midsole includes a plate in contact with the pre-oriented anisotropic foam.

20. 16. The article of footwear of claim 15, wherein the pre-oriented anisotropic foam is formed by at least one of a braided yarn construction or a twisted yarn construction.

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