ARTICLE OF FOOTWEAR WITH ZONAL PROPERTIES FIELD OF THE INVENTION [0001] Aspects herein are directed to an article of footwear comprising a knitted upper that has zonal properties that may provide enhanced performance characteristics related to grip, durability, and/or weight. BACKGROUND OF THE INVENTION [0002] In the realm of footwear design, there is a need to enhance the performance features of a shoe upper, particularly in areas subjected to intense contact and strain during activities such as soccer (global football). While heavy and expensive materials, such as advanced polymers or specialized fabrics, offer optimal levels of friction and durability for these high-impact zones, their use significantly increases the overall weight and cost of a shoe. This presents a dual challenge: firstly, to strategically employ high-performance materials only in critical areas of the shoe upper without compromising on the overall support, durability, and activity-specific requirements like grip and flexibility; and secondly, to configure the remaining areas of the upper using lighter, cost-effective, yet sufficiently robust materials. Additional considerations include maintaining comfort, water resistance, and ergonomic fit while adhering to sustainable manufacturing practices. BRIEF DESCRIPTION OF THE DRAWINGS [0003] Examples of aspects herein are described in detail below with reference to the attached drawing figures, wherein: [0004] FIG. 1A illustrates a medial view of an example article of footwear, in accordance with aspects herein; [0005] FIG. 1B illustrates a lateral view of the example article of footwear of FIG. 1A, in accordance with aspects herein; [0006] FIG.2 illustrates a top view of an upper of the article of footwear of FIGS.1A and 1B, in accordance with aspects herein; [0007] FIG.3A illustrates a cross-sectional view taken along cut-line 3A-3A of the upper of FIG.2, in accordance with aspects herein; [0008] FIG.3B illustrates a cross-sectional view taken along cut-line 3B-3B of the upper of FIG.2, in accordance with aspects herein;
[0009] FIG.4 illustrates an example stitch notation diagram that can be used to form a portion of an area of the upper of FIG.2, in accordance with aspects herein; and [0010] FIG.5 illustrates a block diagram of an example method of manufacturing an upper and/or article of footwear, in accordance with aspects herein. DETAILED DESCRIPTION OF THE INVENTION [0011] In brief, and at a high level, disclosed herein are knit textiles, uppers, and articles of footwear that are formed to include one or more zones having distinct zonal properties, along with methods of manufacturing the same, among other things. For example, in some aspects, an article of footwear with an upper that includes yarns and/or knit structures that enhance the upper’s ability to grip, which is helpful for ball control and precision during ball-handling activities such as dribbling, passing, and shooting, is provided, among other things. In aspects, an upper can include a knit textile that includes at least a first area and a second area that extends adjacent, e.g., directly adjacent to, the first area, e.g., through at least part of a midfoot region of the upper. In some aspects, an upper can include a knit textile of unitary knit construction. In some aspects, an upper can include a knit textile of a composite knit construction, e.g., with multiple knit textile pieces formed and attached together, e.g., via sewing. In some aspects, optionally, the first area may extend into and/or through at least a forefoot region and/or a midfoot region and/or to an ankle opening of the upper. In some aspects, the first area may extend at least partially into and/or through a medial side and/or a lateral side of the upper. In aspects, the second area may extend through at least a midfoot region and/or a heel region, e.g., on a lateral side of the upper. In aspects, a knit textile as described herein may also include a third area that extends through a midfoot region and/or a heel region, e.g., on a medial side of the upper. In aspects, the third area can extend directly adjacent to a first area, e.g., in at least a portion of a midfoot region. In accordance with aspects herein, the first area, the second area, and the optional third area may be integrally knitted with each other during a single knitting process, or may be formed through attachment of separately knitted piece as a composite construction, or through a combination of such techniques. [0012] In aspects, each area of a knit textile as described herein may include yarns and/or knit structures that impart one or more functional characteristics to the corresponding areas. For example, in certain sports such as soccer, an upper is often subjected to varying degrees of contact and stress, primarily due to the nature of the sport, which involves diverse foot movements and interactions with a game ball. These varying degrees of contact can lead to specific material and/or performance needs in different regions of the upper. For example, a toe region, a top overfoot portion, and/or sides of
the upper, particularly those parts used for kicking, often endure the most direct and forceful interactions with a game ball. Within these areas, it can be desirable to use materials and constructions that can withstand repeated impacts and at the same time help provide desired ball control and feedback when striking or controlling a game ball. In addition, certain parts of an upper, e.g., where a foot bends, may constantly be exposed to flexing during running, turning, and striking activities. These parts of the upper can benefit from materials that are not only durable but also flexible, to allow for desired foot movements. In addition, parts around the heel and arch that are less involved in direct ball contact but that help with providing stability and support may benefit from certain zonal characteristics, e.g., such as stiffness and support. [0013] In aspects, to help impart durability and grip characteristics to a toe region, a top overfoot portion, and/or at least the sides of an upper, a first area of a knit textile of the upper may have a thickness (e.g., measured between the outer-facing surface and the inner-facing surface of the knit textile) that is greater than a thickness of one or more other areas (e.g., a second area of the upper among other possible areas of the upper). An outer-facing surface of the knit textile in the first area may also have a coefficient of friction (COF) that is greater than a COF of one or more other areas of the outer-facing surface (e.g., the second area) measured using the same test under the same conditions (e.g., a dry coefficient of friction test or a wet coefficient of friction test). In aspects, by incorporating thicker materials (e.g., a double knit structure, e.g., including a thermoplastic elastomer with gripping characteristics) in the first area of the upper, the first area can generally be more resistant to wear and tear and thus more durable. In high-impact areas where a ball is frequently contacted or controlled, such as the first area of the aforementioned upper, this increased durability can help a corresponding article of footwear maintain its integrity and functionality over a longer period of use. In addition, having a higher COF in certain areas can also help improve grip on a ball. This is beneficial and helpful for precise dribbling, passing, and shooting. In aspects, providing extra grip on a surface of an upper can allow players to apply spin or subtle directional changes to a ball more effectively. As a shoe endures repeated impacts in certain high-impact areas, a thicker material with a higher COF can help maintain performance characteristics better than thinner materials with relatively lower grip or traction properties. This in turn allows a shoe’s performance, e.g., in terms of ball handling and sustained performance, to remain more consistent. For example, in aspects, a first area of an upper can be used to help provide the resilience desired to withstand constant striking of a ball, helping durability such that the first area will not degrade as quickly and continues to offer consistent performance at a toe end of the upper. In aspects, the first area can extend at least partially through or across medial and lateral sides of an upper, e.g., areas often used for ball control and
passing; and a relatively higher COF outer-facing surface in the first area can help enhance grip, allowing players to manipulate a game ball with more finesse and accuracy. [0014] In aspects, materials and/or knit structures used in a first area that contribute to increased thickness and/or COF may create a textile with greater weight. To help reduce the weight of an upper and article of footwear, other areas of the upper, such as the second and third areas, may be formed with a single knit structure to reduce thickness and/or can be formed using different and lighter yarns. For example, optionally, second and third areas can be formed with a high-tenacity yarn to help maintain a lighter weight and higher durability. High-tenacity yarns are known for their beneficial strength-to-weight ratio while also still being relatively flexible. In aspects, second and third areas may include a yarn with a thermoplastic material different than a thermoplastic elastomer used in a first area and/or may have a smaller diameter. With such optional constructions, the second and third areas can provide strength and durability with reduced bulk or weight compared to the first area(s). In addition, through being at least partially or directly adjacent to the first area, the second and third areas can provide support and protection for the wearer, while also allowing the transition between different materials to feel seamless with a reduced impression or feel of there being a transition in performance. The second and third areas can also optionally offer a degree of flexibility that allows for natural foot movement adjacent to a high-impact area, e.g., the first area(s). Furthermore, in aspects, the first area can optionally be seamlessly joined to the second area and the third area through intarsia, which enables isolation of yarns in the first, second, and third areas while maintaining a course direction across those areas. [0015] For improved comfort and fit, a knitted upper may optionally include a fourth area, which in aspects can extend through at least part of a throat area and/or to an ankle opening. In aspects, the fourth area can at least partially circumscribe an edge of an ankle opening, which may be formed of at least one yarn that has elastic properties, e.g., elastane or another elastic yarn. The fourth area may include a single knit structure, e.g., a single Jersey knit construction, or may include a double knit structure, e.g., a double Jersey knit construction. Incorporating a yarn with elastic properties, e.g., such as elastane yarns, can allow certain parts of the upper to more readily stretch and conform to the shape of a wearer’s foot and ankle. It can also allow the throat and ankle regions of a footwear article to more readily flex and move with a wearer’s foot, helping to reduce pressure points and limit constriction. This is especially beneficial during dynamic movements that occur during sports and other activities. [0016] As used herein, an article of footwear generally includes a sole structure secured to an upper. A biteline of the upper represents where the upper meets the sole structure. The article of
footwear described herein may comprise a soccer shoe, a running shoe, a baseball shoe, a basketball shoe, a skateboarding shoe, a cycling shoe, an American football shoe, a tennis shoe, a global football shoe, a training shoe, a walking shoe, a hiking shoe, and the like. The concepts described herein may also be applied to other footwear types that are considered non-athletic such as dress shoes, loafers, sandals, and work boots. As used herein, the article of footwear may be divided into different general regions. A forefoot region generally includes portions of the article of footwear that correspond to the toes and joints connecting the metatarsals with the phalanges. A midfoot region generally includes portions of the article of footwear corresponding with an arch area and an instep area of the foot. A heel region generally corresponds with rear portions of the foot including the calcaneus bone. The article of footwear described herein may include a lateral side that corresponds with an outside area of the foot (i.e., the surface that faces away from the other foot) and a medial side that corresponds with an inside area of the foot (i.e., the surface that faces toward the other foot). The different regions and sides described above are intended to represent general areas of footwear to aid in the following discussion and are not intended to demarcate precise areas. The different regions and sides may be applied to the article of footwear as a whole, to the knitted upper, and to the sole structure. [0017] As used herein, the term “throat area” refers to an area on a top (upward-facing) side of an upper generally extending between an ankle opening and a forefoot region. The throat area may include an opening formed between a lateral side and medial side of the upper when formed into the shape of the article of footwear, and in some aspects, the throat area may include a tongue extending across the opening in the throat area. In some aspects, the throat area does not have an opening but, rather, includes a continuous integrally knit area of a knit component extending between the medial and lateral sides, e.g., one that can be formed of elastic yarns, material, and/or other components that include a degree of stretchability. [0018] As used herein, the term “perimeter” refers to an area forming the boundary of the object referred to. For example, a perimeter of a knitted component is the area that extends along the boundary of that structure. The “outer perimeter” may refer to portions of a perimeter of a knitted component that, once formed into an article of footwear, are secured to the sole structure or form a seam between two ends of the outer perimeter (such that they may at least partially extend under the foot of the wearer when the article of footwear is worn. In contrast, an “inner perimeter” may refer to portions of the perimeter of a knitted component that, once formed into an article of footwear, define openings, such as an opening in a throat area and/or the ankle opening. The
perimeter (outer perimeter or inner perimeter) may refer to an edge of the knitted component or to a peripheral area adjacent to the edge. [0019] The term “outer-facing surface” as used herein means a surface of the knitted upper or article of footwear that faces the external environment. In some aspects, the outer-facing surface may mean the outermost-facing surface of the knitted upper or article of footwear. The term “inner- facing surface” as used herein means a surface of the knitted upper or article of footwear that faces a void for receiving the wearer’s foot. In some aspects, the inner-facing surface may mean the innermost-facing surface of the knitted upper or article of footwear. [0020] The term “knit” such as used is herein to describe the knitted upper refers to a textile piece that is formed from at least one yarn that is manipulated (e.g., with a knitting machine) to form a plurality of intermeshed loops (also known as interlooping) that define courses and wales. The term "course," as used herein, refers to a predominantly horizontal row of knit loops (in an upright textile as it is knit on the knitting machine) that is produced by adjacent needles during the same knitting cycle. The course may comprise one or more stitch types, such as a knit stitch, a missed stitch, a tuck stitch, a transfer stitch, a rib stitch, and the like, as these terms are known in the art of knitting. The term “course-wise direction” refers to a direction that is parallel to the knit courses of the textile piece. The term "wale," as used herein, is a predominantly vertical column of intermeshed or interlooped knit loops, generally produced by the same needle at successive (but not necessarily all) courses or knitting cycles. The term “wale-wise direction” refers to a direction that is parallel to the knit wales of the textile piece. [0021] The term “double knit construction” as used herein refers to a knit construction that is generally formed on at least two needle beds of a knitting machine (e.g., a multi-bed construction). Such multi-bed knit constructions may be characterized by two opposing faces of knit loops and/or tucks, e.g., one face of loops formed on a first needle bed, and a second face of loops formed on a second needle bed. In example aspects, the two faces may be joined by yarns that interloop with yarns in both the first face and the second face of the double knit construction. Common double knit constructions include double jersey, rib, interlock, cardigan, other “double-bed” knit structures initially formed on at least two needle beds, and other knit structures having two opposing faces of knit loops or tucks, including full-gauge and less-than-full-gauge variations of those structures. The term “single knit construction” as used herein refers to a knit construction generally formed on a single needle bed (i.e., a single-bed construction). Common single knit constructions include single jersey. [0022] The term "integrally knit," as used herein, may mean a knit textile having a yarn from one or more knit courses in a first area or zone being interlooped with one or more knit courses of another
area or zone. The interlooping may be through a simple knit stitch, a tuck stitch, a held stitch, a float or miss stitch, and the like. In this way, areas or zones that are integrally knit together may have a seamless transition such that they seamlessly extend from one another in one or more example aspects. [0023] Forming the upper using a knit construction may provide advantages including, but not limited to, a particular degree of elasticity (for example, as expressed in terms of Young’s modulus where a greater Young’s modulus correlates to being more stiff), breathability, bendability, strength, moisture absorption, weight, abrasion resistance, and/or a combination thereof. These characteristics may be accomplished by selecting a particular knit structure, by varying the size and tension of the knit structure, by using one or more yarns formed of a particular material (e.g., a polyester material, a relatively inelastic material, or a relatively elastic material such as elasticated yarns, which is a thermoplastic material), by selecting yarns of a particular size (e.g., denier), and/or a combination thereof. Using a knit construction may also provide desirable aesthetic characteristics by incorporating yarns having different colors, textures or other visual properties arranged in a particular pattern. The yarns themselves and/or the knit structure formed by one or more of the yarns may be varied at different locations such that the knitted upper may have different properties as described herein. [0024] The yarns in accordance with aspects herein may include monofilament yarns and/or multifilament yarns formed from, for example, synthetic materials. In example aspects, the fourth area may be knit using an elastane yarn. In other example aspects, at least some areas, such as the first area, the second area, and the third area, may comprise a high-tenacity yarn having a tenacity of, for example, about 5 grams/denier or greater. In some example aspects, the high-tenacity yarn may be produced from 100% recycled polyester (e.g., made using post-consumer water bottles that are converted into yarn), have a tenacity of about 6.7 grams/denier, and/or a denier of about 330. [0025] Further, in example aspects, the yarns used in various areas, including yarns described above, may be generally described as high-melting yarns or low-melting yarns. As used herein, the term “high-melting” generally means that the yarns melt at about 180 degrees Celsius or higher. These yarns may include high-melting thermoplastic yarns that include high-melting polyethylene terephthalate (PET) (commonly referred to as polyester) yarns, high-melting recycled PET yarns, cushioning yarns, core/sheath yarns in which the core comprises a high-melting material (e.g., a high- melting PET core), elastane yarns, and other high-melting synthetic, thermoplastic yarns. Unless otherwise indicated, references to a “high-tenacity yarn” herein generally refer to a high-melting yarn.
[0026] Low-melting yarns generally comprise low-melting thermoplastic yarns. As used herein, the term “low-melting” generally means yarns that melt at about 175 degrees Celsius or less. The low- melting thermoplastic yarns comprise a synthetic polymeric material formed from a polymer that melts at relatively low temperatures. In example aspects, the low-melting yarns may include yarns that are entirely formed from a low-melting thermoplastic material such as low-melting PET or low- melting polyamide (such as nylon). Low-melting yarns may also include low-melting thermoplastic material covering yarns having a high-melting material formed from, for example, high-melting PET. For instance, an example yarn that may be knit in the second and third areas includes a high-melting nylon core surrounded by a low-melting thermoplastic polyurethane (TPU). Another example yarn, which may be knit in the first area, includes a high-melting high-tenacity PET surrounded by a thermoplastic elastomeric composition, such as TPU or styrene-ethylene-butylene-styrene (SEBS). In example aspects, the melting temperature of the thermoplastic material may be sufficiently different from the melting temperature of the high-melting yarns that the thermoplastic material of the low- melting yarns may be essentially completely melted without melting or adversely affecting (e.g., burning, charring, or singeing) the characteristics of the high-melting yarns. Similarly, the melting temperature of the thermoplastic material may be sufficiently different from the melting temperature of any high-melting material in the low-melting yarns (e.g., core) so that the thermoplastic material may be essentially completely melted without melting or adversely affecting (e.g., burning, charring, or singeing) the characteristics of the high-melting material of the same yarn. [0027] Different areas of the upper may include low-melting yarns with different thermoplastic compositions, melting temperatures, structures, and/or sizes. A first thermoplastic yarn knit in the first area may comprise a first thermoplastic elastomeric (TPE) composition. In example aspects, the first thermoplastic elastomeric (TPE) composition comprises TPU. In other examples, the first thermoplastic elastomeric composition comprises SEBS. The first TPE composition may surround a core of high-melting PET. The first TPE composition may have a melting temperature of 170 degrees Celsius or less. In one example, the melting temperature is around 160 degrees Celsius. [0028] A second thermoplastic yarn knit in the second area may comprise a second TPE composition. In example aspects, the second TPE comprises TPU. The second TPE composition may surround a core of high-melting nylon. The second TPE composition may be extruded with the high- melting core, whereas the first TPE composition of the first thermoplastic yarn may be coated around the high-melting core. The second TPE composition may have a melting temperature of about 175 degrees Celsius.
[0029] There may be other differences between the first thermoplastic yarn and the second thermoplastic yarn. For example, the second thermoplastic yarn may have a smaller diameter than the first thermoplastic yarn. Additionally, in various aspects, the first TPE composition of the first thermoplastic yarn may have other advantageous properties, which may enhance grip, durability, and/or resiliency. For example, the first TPE composition is a composition of one or more thermoplastic elastomers with a glass transition temperature(s), prior to thermoforming, that is below minus 20 degrees Celsius, which allows the thermoplastic elastomer(s) present to be in their “rubbery” state, even when the knit textile is used in cold environments. [0030] Additionally, the first TPE composition may result in areas having greater gripping properties, e.g., as demonstrated by greater COF values. The COF of a sample can be determined using a test method such as ASTM D1894. In this method, a sample is cut to size and mounted on a sled, and a 100-gram weight plate is placed on the sled. During the test, the weighted sled is pulled across a test surface of the material being tested. For example, static and dynamic or wet and dry COFs may be determined by pulling the sled across a concrete surface to determine the COF of the sample and concrete. The coefficient of friction of the sample against that surface is captured by recording the normal force (100 grams plus sled weight) and measuring the applied force required to drag the sled across the test surface. The COF is then calculated from the ratio of the two forces. Dry COF is determined by testing a dry sample against a dry testing surface, and wet COF is determined by testing a sample wetted with water by soaking it in room temperature water for ten minutes against a test surface wetted with room temperature water. [0031] The term “thermoformed” refers to a generally unitary or continuous structure formed after pressure is applied to the melted thermoplastic material of the yarns and after the melted thermoplastic material has hardened upon cooling. As such, the cooled structure may comprise the same polymeric material as the thermoplastic material used to form the yarns (e.g., TPU, TPE, and the like). [0032] Example aspects herein may include varying visual effects in different areas of the knitted component. In example aspects, the monofilament yarns and/or multifilament yarns used in various areas include one or more visual components configured to facilitate translucency or transparency of the area and may include, for example, transparency, color, haze, gloss, and/or reflectivity. The visual component may be afforded by the material that forms the monofilament and/or multifilament yarn or may be imparted to the monofilament and/or multifilament yarn by using an application technique compatible with both a respective visual component and the monofilament and/or multifilament yarn. In one aspect, a visual component may be afforded by a material that interacts with light in a manner
such that the monofilament and/or multifilament yarn included in the material may be reflective, clear, glossy, metallic, exhibiting shimmer, and the like. In another aspect, a visual component may be imparted by dyes, inks, pigments, finishes, and the like, such that the monofilament and/or multifilament yarn may be a light color (e.g., white and light shades of grey, red, orange, yellow, green, and blue), reflective, glossy, metallic, and the like. [0033] In some examples, certain area(s) of the knit textile may have more translucency or transparency than others. Such transparency or translucency may be due to translucent or transparent materials, such as yarn or a film, which may be created from melting material on a yarn, and/or may be due to the structure of the knit textile. For example, a more open knit structure will provide more translucency than a denser knit structure. “Transparent” and “transparency,” as used herein with respect to a material, such as a yarn, refers to the property of materials that allows light to pass through them without significant scattering or absorption. Transparent objects permit the transmission of light waves, enabling objects to be seen clearly through them. “Translucent” and “translucency,” as used herein with respect to a material, such as a yarn, refers to the property of materials that allows some light to penetrate through them, but the light is scattered or diffused. This diffusion of light results in objects being visible through them, but not as clearly defined as they would be through transparent materials. When referring to an area or region of a knitted structure, “translucent” or “translucency” refers to the ability to let some light pass through, either through openings in the knit structure (either openings inherent between adjacent loops in a knit structure or intentionally formed openings) and/or through translucent or transparent material, such as a translucent or transparent film. Translucency may determined through an ASTM D1746 test. “Opaque,” as used herein with respect to a material such as a yarn, refers to the property of a material that prevents light from passing or transmitting when light strikes the surface, such that all of the light is diffused and/or absorbed. [0034] Unless indicated otherwise, all measurements provided herein are taken when the upper and/or article of footwear is at standard ambient temperature and pressure (298.15 K and 100 kPa) and is in a resting (non-tensioned) state. As used herein, the terms “substantially” and “about” mean within ± 10% of an indicated value. [0035] FIGS.1A and 1B respectively schematically depict a medial view and a lateral view of an example article of footwear 100 having a knitted upper 110 and a sole structure 112 secured to the knitted upper 110. The knitted upper 110 includes an outer-facing surface 111 and an inner-facing surface 113. The article of footwear 100 is shown in the form of an athletic shoe but other types of shoes (e.g., sandals, leisure shoes, and the like) are contemplated herein. The article of footwear 100
includes a forefoot region 114 having a toe end 115, midfoot region 116, a heel region 118, a medial side 120, and a lateral side 122. The article of footwear 100 includes a biteline 117, a collar 124, an ankle opening 125 for receiving a wearer’s foot, and a throat area 126. [0036] In aspects, an article of footwear, e.g., the article of footwear 100 shown in FIGS.1A and 1B, can include additional elements layered on top of an upper of the article of footwear, e.g., the knitted upper 110. This can include, for example, leather materials, synthetic leather materials, knitted and/or woven textiles, skins, sheets, films, and/or printing, and the like. For example, in some aspects, a skin or skin layer, e.g., one that includes a polymer material such as a polyurethane (PU) or a TPU, can be bonded or joined to a surface of a knit textile forming part of a knitted upper. In some aspects, a knitted upper can be constructed from two or more separately knitted pieces, e.g., an upper foot portion and a lower foot portion, e.g., that extends to either a bite-line or underfoot. In some aspects, such upper and lower portions can be joined together via a seam. In other aspects, a knitted upper may be formed of a unitary knit construction. In some aspects, a skin or skin layer can be bonded to a knit textile using a TPU hot-melt adhesive, e.g., applied to an outer surface of the knitted upper and under the skin or skin layer. In aspects, the TPU hot-melt adhesive can be a TPU that melts when subjected to its melting temperature which is lower than the melting temperature of other materials, e.g., the skin or skin layer and/or the yarns in the knitted upper. In some aspects, a PU skin can be applied over a TPU hot-melt adhesive, and together these layers can be melted and bonded onto a knit upper, e.g., using applied heat or using high-frequency processing where high-frequency vibrations generate heat to facilitate melting and adhesion. In some aspects, a TPU hot-melt and/or a PU skin can be applied onto a polyester (PET) component of a knit upper. In aspects where a knitted upper is constructed from two or more separately knitted pieces, the TPU hot-melt and/or PU skin layer can extend across a connection or seam that joins the separate pieces to help provide structural integrity and adhesion across the composite knit construction. These and other additional elements may be positioned at discrete locations on an upper, e.g., the knitted upper 110 including, for example, at the toe end 115 (e.g., a toe cap), the heel region 118 (e.g., a heel counter), and/or another location. [0037] In example aspects, the upper 110 may comprise a knit textile. In some example aspects, the upper 110 may comprise a knit textile of unitary construction and may be formed in a single knitting process. The knitted upper 110 includes a first area 131, a second area 132, a third area 133, a fourth area 134, a fifth area 135, and a sixth area 136. The first, second, third, fourth, fifth, and sixth areas 131, 132, 133, 134, 135, and 136 are depicted schematically and are provided to illustrate the general locations of the areas on the knitted upper 110. Additional features of the aforementioned areas are shown in at least FIG.2.
[0038] As discussed earlier, the first area 131 is located in the forefoot region 114 of the upper 110 and extends from the toe end 115 along each of the medial side 120 and the lateral side 122 of the upper 110 in the forefoot region 114. The location of the first area 131 may correspond to an area of the upper 110 that is considered high impact in certain activities, such as soccer. In some aspects, the first area 131 within the forefoot region 114 extends from a forward-most end of the upper 110 at the toe end 115 to a forward portion of the throat area 126. In some aspects, the first area 131 extends at least partially in the medial side 120 and the lateral side 122 in the midfoot region 116. In some aspects, the first area 131 may extend in the forefoot region 114 from the biteline 117 on the medial side 120 of the upper 110 to the biteline 117 on the lateral side 122 of the upper 110. In some aspects, the first area 131 may be contiguous with the second area 132. For example, in some aspects, the first area 131 extends directly adjacent at least part of the throat area 126 through at least the midfoot region 116. In some aspects, the first area 131 in the midfoot region 116 does not extend to the biteline 117. In some aspects, the first area 131 extends through the midfoot region 116 to the collar 124 that at least partially defines the ankle opening 125. In some aspects, although not explicitly depicted, when more grip may be desired, the first area 131 may be knit to extend a greater distance toward the biteline 117 in the midfoot region 116 on the medial side 120 of upper 110 than the lateral side 122 of the upper 110. [0039] The second area 132 seamlessly extends from the first area 131 on the lateral side 122 of the upper 110, and the third area 133 seamlessly extends from the first area 131 on the medial side 120 of the upper 110. The second and third areas 132 and 133 may generally be located in the midfoot region 116 of the upper 110 and extend through at least the midfoot region 116 and the heel region 118 of the upper 110. In some aspects, the third area 133 may be contiguous with the first area 131. In example aspects, the second and third areas 132 and 133 may extend directly adjacent the first area 131 through at least part of the midfoot region 116. In example aspects, the second and third areas 132 and 133 may extend from the first area 131 to the biteline 117 where the upper 110 is secured to the sole structure 112. In other example aspects, the second and third areas 132 and 133 may extend directly adjacent the fifth area 135 and/or the sixth area 136 in at least part of the heel region 118. In some example aspects, two or more edges of the second area 132 may converge adjacent the fourth area 134 with an edge of the first area 131 and/or an edge of the fifth area 135. In example aspects, the second area 132 may extend from the biteline 117 in the heel region 118 to the sixth area 136. [0040] To impart durability and grip features, at least a portion of the first area 131 may have a first yarn (which may be referred to as a first low-melting yarn) comprising a first TPE composition. In some aspects, the first low-melting yarn may comprise a core of high-melting yarn, such as PET, and a
sheath of a low-melting thermoplastic material, such as TPU or SEBS. In some aspects, the sheath may comprise a coating of rubberized TPU. The melting temperature of the first TPE composition may be about 160 degrees Celsius. The first TPE coating may form a majority of the first low-melting yarn. For instance, the first TPE composition may be about 88%, while the high-melting core may be about 12%. The first low-melting yarn may have a denier of at least 1000 grams/denier, such as about 1275 grams/denier. [0041] In addition to the first low-melting yarn, the first area 131 may comprise a first high- melting yarn in that the high-melting yarn may have a higher melting temperature than the low- melting TPE composition of the first low-melting yarn. In example aspects, the first high-melting yarn be a high-melting polyester. Additionally, the first high-melting yarn may be a high-tenacity yarn, such as a high-tenacity polyester. [0042] Further, in various aspects, the first area 131 may comprise a double knit structure. The double knit structure may allow the first low-melting yarn and the first high-melting yarn to alternate which yarn is exposed on the outer-facing surface 111. For example, the first low-melting yarn may provide enhanced grip, and balancing the enhanced grip across the outer-facing surface 111 with another material may achieve a desired level of grip for a particular activity. In example aspects, to provide the optimal level of grip, the first high-melting yarn is exposed on the outer-facing surface 111 on about half of the first area 131 (see white areas 141), and the first low-melting yarn with the first TPE composition is exposed on the outer-facing surface 111 on about half of the first area 131 (see black areas 140). In such examples, the first high-melting yarn may be knit on an inner-facing surface 113 of the upper 110 at locations where the first low-melting yarn is knit on the outer-facing surface 111 and vice versa. In the example shown, the areas 140 of the first low-melting yarn alternate with the areas 141 of the high-melting yarn. Additionally, a double knit structure may also provide additional structure compared to a single knit structure. [0043] In various aspects, heat and/or pressure may be applied to at least the first area 131 to at least partially melt the first TPE composition of the first yarn within areas 140. The melted TPE composition may be reflowed and cooled (e.g., softened and solidified) to form a thermoformed network of yarns, where the first TPE composition at least partially surrounds and connects adjacent loops of the high-melting core and the first high-melting yarn within the first area 131. For example, in some aspects, a TPE composition can be subjected to a melting or deformation temperature such that the thermoplastic elastomer melts, softens, flows, re-shapes, and then cools and solidifies into a shape at least partially different than its original shape. Following thermoforming the first area (e.g., at around 135 degrees Celsius), the first TPE composition forms a film that covers the outer-facing
surface 111 of the upper 110 in the first area 131. The film covering the outer-facing surface 111 provides a relatively higher COF to the outer-facing surface 111 of the upper 110 in the first area 131 (e.g., enhancing a gripping performance feature) than other areas, such as areas 132, 133, 134, 135, and 136 that don’t include the first TPE composition. [0044] To reduce the weight of the shoe while retaining some performance and durability features, at least a portion of the second area 132 may have a single knit structure comprising a high- tenacity yarn. The high-tenacity yarn may be the same high-tenacity yarn used in the first area 131 or may be a different high-tenacity yarn. The high-tenacity yarn may have a relatively high melting temperature compared to other yarns in the second area 132 and, therefore, may be referred to herein as the second high-melting yarn. [0045] In some aspects, the single knit structure of the second area 132 may further comprise a second low-melting yarn having a second TPE composition that is different than the first TPE composition of the first area 131. For example, the second low-melting yarn of the second area 132 may include a co-extruded yarn with a nylon core and a TPU sheath (e.g., about 50% nylon and about 50% TPU). In example aspects, the second low-melting yarn of the second area 132 may have a diameter less than the diameter of the first low-melting yarn. In some examples, the second low- melting yarn has a diameter of about 0.20 mm. The second low-melting yarn may also have a smaller denier than the first low-melting yarn. In various aspects, the second low-melting yarn may have a denier that is less than 750 and in some examples, is about 350. Further, the second TPE composition may have a greater melting temperature than the first TPE composition. In one example, the second TPE composition has a melting temperature of about 175 degrees Celsius. When thermoforming at around 135 degrees Celsius, the second TPE composition of the second area 132 can be pressed (i.e., pressure is applied to the second area 132) to soften or partially melt without completely melting the second TPE composition. An example of a suitable single knit construction incorporating both the high-tenacity yarn and the thermoplastic elastomer composition for the second area 132 is described with regards to the stitch notation diagram of FIG.4. [0046] In some example aspects, the second area 132 may comprise one or more visual components configured to facilitate translucency of the second area 132. For example, in some aspects, translucency to the second area 132 may be provided by a single knit structure that is relatively more open than some other knit structures (e.g., a double knit structure). For example, the second area 132 may have a lower stitch density (e.g., a lower number of stitches per unit of area) than the first area 131. In some example aspects, a translucency of the second area 132 is greater than a translucency of the first area 131, which may include some translucency or no translucency.
Additionally or alternatively, differences in transparency between the first area 131 and the second area 132 may be due to materials forming the second area 132 compared to the first area 131. In some examples, the second area 132 may be knit with one or more translucent or transparent yarns, which may remain in strand form, while the first area 131 may be knit with one or more opaque yarns. A more translucent second area 132 may provide visibility to a user of additional containment structures within the upper 110, and this visibility may be an indicator to potential wearers whether or not the upper 110 has the desired level of support and structure. [0047] In accordance with aspects herein, depending on the construction and materials of an upper, e.g., the upper 110, different areas of an upper (e.g., the first area 131 and the second area 132) may have different degrees of stiffness. This different stiffness can support desired material properties and performance as described herein. The stiffness can be measured or determined through determination of the Young’s modulus or through using test method ASTM D1388. For example, when the first area 131 and the second area 132 are provided with the yarns and knit constructions of certain aspects described herein, a stiffness of the first area 131 (e.g., a first stiffness) can be less than a stiffness of the second area 132 (e.g., a second stiffness). [0048] It should be noted that the third area 133 may have the similar or same yarns and knit constructions as the second area 132. As such, further details of the third area 133 need not be repeated. However, it should be understood that other aspects of the upper 110 include the third area 133 having different yarns and/or knit constructions than the second area 132. Therefore, references to the materials and/or construction of the third area 133 are made herein in conjunction with the second area 132 for ease, but it will be appreciated that in some aspects, such features are present in the second area 132 without necessarily being in the third area 133. For example, the third area 133 may have a third stiffness that is greater than the first stiffness of the first area 131. In some aspects, the third stiffness is the same as the second stiffness of the second area 132, while in other aspects, the third stiffness is less than the second stiffness but still greater than the first stiffness of the first area 131. [0049] The difference in knit construction yarn types between the first area 131 and the second area 132 may result in some differing characteristics (e.g., the first area 131 having a greater knit density (e.g., a greater number of stitches per unit of area) than the second area 132). For example, in some aspects, a sample (e.g., 1-inch squared sample) of the first area 131 may be about three times heavier than a same-sized sample of the second area 132. In other example aspects, a thickness of the first area 131 may be greater than a thickness of the second area 132, as will be described further in FIGS.3A and 3B. In some example aspects, the outer-facing surface 111 of the upper 110 in the first
area 131 may have a first COF that is greater than a second COF at the outer-facing surface 111 in the second area 132. Each of the weight, thickness, and COF of the first area 131 contributes to its touch, feel, grip, and performance. For example, the greater COF in the first area 131 provides better grip on a ball while the greater thickness and weight provide more durability, structure, and cushioning. The third area 133 may have the same or similar features to the second area (e.g., the third area 133 may have a third COF that is the same as the second COF, and which is less than the first COF). [0050] In order to provide a seamless outer-facing surface 111 of the upper 110 where an athlete may use the footwear 100 to make contact, the first area 131 and the second area 132 may be seamlessly joined together. In example aspects, the first area 131 may be joined to the second area 132 through intarsia having a one-needle, a two-needle, or a greater-than-two-needle overlap between knitted loops of the first area 131 and knitted loops of the second area 132, as described with respect to FIG.5. In some example aspects where the first area 131 and the second area 132 are joined through intarsia with one or more overlapping needles, the yarns of the second area 132 may be knit behind the yarns of the first area 131 to create a strong, straight connection. In other example aspects, the first area 131 and the second area 132 may be joined by tuck stitches or any other suitable way to form a seamless connection. The third area 133 may have the same or similar features to the second area 132. [0051] For improved comfort and fit, example aspects may include the upper 110 having a fourth area 134 that may extend from the throat area 126 into the heel region 118 and around the ankle opening 125. In example aspects, the fourth area 134 may form a central portion of the throat area 126 and the collar 124. The fourth area 134 may at least define the ankle opening 125. In example aspects, the fourth area 134 extends directly adjacent the fifth area 135 in at least part of the heel region 118. In example aspects, the fourth area 134 extends directly adjacent the first area 131 in at least part of the midfoot region 116. In example aspects, the fourth area 134 may have a double knit construction similar to the first area 131 but may have a different stitch sequence and/or include different yarns than the first area 131. For example, the fourth area 134 may comprise an elastane yarn so that the fourth area 134 may have more stretch than the first area 131, the second area 132, and in some aspects, the third area 133. Additionally, the fourth area 134 may exclude the first TPE composition and, in some aspects, may also exclude the second TPE composition. In some example aspects, the fourth area 134 has no direct attachment with a portion of the upper 110 having a single knit construction, as explained further herein. [0052] In example aspects where the fourth area 134 comprises a double knit structure with an elastane yarn, the fifth area 135 may be included to aid in the connection between the fourth area
134 with the single knit structures of one or more of the second area 132, the third area 133, and the sixth area 136. In example aspects, the fifth area 135 may extend from the medial side 120 of the heel region 118 to the lateral side 122 of the heel region 118. In example aspects, the fifth area 135 may be located between the fourth area 134 and the second and/or third areas 132 and 133 in the heel region 118. In example aspects, the fifth area 135 may be located between the fourth area 134 and the sixth area 136 in the heel region 118. In some example aspects, the fifth area 135 may comprise the same or at least some of the same yarns as the second area and/or third areas 132 and 133 but may have a different stitch construction. In some aspects, the fifth area 135 may have one or more yarns that alternate knitting on a front needle bed and a back needle bed. Additionally, the stitch sequence may include knit stitches and held stitches, where the loops are longer than knit stitches due to being retained on a needle for longer. In one example, the fifth area 135 has a Milano stitch sequence, which was determined to provide a stronger connection to the fourth area 134, particularly around a curved boundary such as around the ankle collar 124. [0053] In order to provide lightweight support to a low-impact area in the heel region 118 of the upper 110, the sixth area 136 may be included and extend from the medial side 120 in the heel region 118 to the lateral side 122 in the heel region 118. In example aspects, the sixth area 136 may be located between the fifth area 135 and one or more of the second and third areas 132 and 133. In example aspects, the sixth area 136 may extend directly adjacent the fifth area 135 and the second and third areas 132 and 133 in at least part of the heel region 118. In example aspects, the sixth area 136 may comprise a single knit structure and may have the same or similar knit sequence as the sixth area 136. The sixth area 136 may include wedging or goring, not needed in the second and third areas 132 and 133, to create three-dimensional shape around the wearer’s heel. Additionally, the sixth area 136 may include at least some of the same yarns as the first and third areas 132 and 133. For example, the sixth area 136 may include the second high-melting yarn, which may be a high-tenacity yarn, in order to provide a knit structure that is lightweight, yet durable. The sixth area 136 may also include the second low-melting yarn. In some examples, the sixth area 136 includes a higher concentration of the second TPE composition than the second and third areas 134 to provide additional rigidity to the heel region. In other examples, the sixth area 136 may be substantially the same as the second and third areas 132 and 133 and, as such, be considered extensions of the second and third areas 132 and 133. [0054] FIG.2 depicts the knitted upper 110 of FIG.1 before being secured to the sole structure 112. In example aspects, the knitted upper 110 may have a generally U-shaped configuration that is outlined by an outer perimeter edge 210, a pair of heel edges 212, and an inner edge 214. The U-
shaped configuration is just one example shape of the knitted upper 110, and other example shapes are contemplated herein. When incorporated into the article of footwear 100, the outer perimeter edge 210 may be positioned against the upper surface of the sole structure 112 and may be joined to a strobel in example aspects. In other aspects, the knitted upper 110 may include an underfoot portion. In this example, the article of footwear 100 may not include a strobel. In example aspects, the outer perimeter edge 210 comprises a double knit structure to aid in securing the upper 110 to a jig, the sole structure 112, and the pair of heel edges 212. In example aspects, the pair of heel edges 212 are joined to each other and extend generally vertically in the heel region 118 of the article of footwear 100. The inner edge 214 forms the ankle collar 124. The knitted upper 110 includes a first surface 216 that corresponds to the outer-facing surface 111 of the article of footwear 100 and an opposite second surface 217 that corresponds to the inner-facing surface 113 of the article of footwear 100. [0055] Still referring to FIG.2, a center midline 220 is provided that divides the upper 110 in half between the medial side 120 and the lateral side 122 for illustrative purposes. As depicted, the first area 131 extends a greater distance (e.g., a first distance 222) in a medial-to-lateral direction, which may correspond to the course-wise direction, in the forefoot region 114 than in the midfoot region 116 (e.g., a second distance 224). Also depicted is the third area 133 extending a greater distance (e.g., a third distance 226) in the medial-to-lateral direction in the heel region 118 than in the midfoot region (e.g., a fourth distance 228). In some example aspects, the first distance 222 in the forefoot region 114 may be greater than any distance in the medial-to-lateral direction from the center midline 220 to an edge of the first area 131. In some example aspects, the third distance 226 in the heel region 118 may be greater than any distance in the medial-to-lateral direction in the midfoot region 116 between the center midline 220 to an edge of the third area 133. It can be appreciated that, although reference is made only to the half of the upper 110 on the medial side 120, the same features are present in the second area 132 on the lateral side 122. [0056] FIGS.3A-3B illustrate cross-sectional views of the upper 110 of FIG.2 in order to show the varying thicknesses of the knit structures within the upper 110. As depicted, FIG.3A illustrates a cross- sectional view in the forefoot region 114 while FIG.3B illustrates a cross-sectional view in the midfoot region 116. A thickness of the upper 110 may be measured between the first surface 216 and the second surface 217. As seen in FIG.3A, in some example aspects, the thickness of the upper 110 in the forefoot region 114 remains constant. For example, a first thickness 301 of the first area 131 may extend across the entirety of the upper 110 in the lateral-to-medial direction (which may be the
course-wise direction) in the forefoot region 114, and the first thickness 301 may remain generally constant across the forefoot region 114. [0057] As seen in FIG.3B, in some example aspects, a thickness of the upper 110 in the midfoot region 116 varies and does not remain constant. In example aspects, a second thickness 302 of the second area 132 may be less than the first thickness 301. In some example aspects, the second thickness 302 may be no more than half the thickness of the first thickness 301. In one example, the second thickness 302 is about one-third of the first thickness 301. In example aspects, a third thickness 303 of the third area 133 may be the same thickness as the second thickness 302. In some example aspects, a fourth thickness 304 of the fourth area 134 may have substantially the same thickness as the first thickness 301. In example aspects, the outer perimeter edge 210 may have a double knit structure with an edge thickness 310 that is less than the first thickness 301 but is more than the second thickness 302 and the third thickness 303. As depicted, there may be at least one, two, three, or four transitions between different thicknesses in the midfoot region 116 between different areas of the upper 110 having different knit constructions and compositions. [0058] FIG.4 depicts an example stitch notation diagram 400 that is repeatable and may be used to form a portion of the second area of the upper of FIG.2. The stitch notation diagram 400 includes rows 401-408 that include representations of needles on a single needle bed (e.g., on a front or a rear bed) of a knitting machine. In example aspects, the rows 401-408 are knit only on a rear bed on the knitting machine in order to facilitate the seamless transition described above between the first area 131 and the second area 132. Each of these rows may represent a pass of a feeder of the knitting machine. Representations of a second needle bed (e.g., a front needle bed) are omitted from FIG.4. [0059] Rows 401, 404, 405, and 408 may represent a high-melting yarn 410 (that is the same or similar to the first high-melting yarn discussed previously with regards to the second area 132) knit to at least partially form the single knit construction of the second area 132. Rows 402, 403, 406, and 407 may represent a low-melting yarn 412 that is the same or similar to the second low-melting yarn discussed previously with regards to the second area 132. [0060] In example aspects, separate feeders are used for the high-melting yarn 410 (e.g., a first feeder) and the low-melting yarn 412 (e.g., a second feeder). In a first pass of the feeders, the first feeder knits the high-melting yarn 410 on odd needles (e.g., example odd needle 420) and floats the high-melting yarn 410 across even needles (e.g., example even needle 422) in row 401 while the second feeder knits the low-melting yarn 412 on even needles and floats the low-melting yarn 412 across odd needles in row 402. After the first pass of each feeder (i.e., rows 401 and 402), each needle
on the single needle bed represented in FIG.4 would hold one loop of yarn – either a loop of the high- melting yarn 410 or a loop of the low-melting yarn 412. [0061] With the second pass of each feeder, the respective feeder switches the needles on which it knits. That is, in a second pass, the first feeder knits the high-melting yarn 410 on even needles and floats the high-melting yarn 410 across odd needles in row 404 while the second feeder knits the low- melting yarn 412 on odd needles and floats the low-melting yarn 412 across even needles in row 403. After the second pass, for example, each needle on the single needle bed represented in FIG.4 would have one knit loop of high-melting yarn 410 and one knit loop of yarn 412. In a third pass of the feeders, the knit loops from the first pass and the second pass are released, and the first feeder knits row 405 the same way as row 401 while the second feeder knits row 406 the same way as row 402. In a fourth pass, the first feeder knits the high-melting yarn 410 only on every one in four needles (e.g., knits on an even needle, floats across three needles, and then knits on another even needle) in row 408 while the second feeder knits the low-melting yarn 412 the same way as row 403 (knits on odd needles and floats across even needles) in row 407. At the end of the fourth pass, three out of four needles on the single needle bed represented in FIG.4 will have a knit loop of the high-melting yarn 410 and a knit loop of the low-melting yarn 412 while one out of four needles will only have a knit loop of the low-melting yarn 412. Skipping additional needles for the pass of the high-melting yarn 410 in row 408 creates longer floats, which may decrease stretch as well as creating a linear visual effect. In other examples, however, row 408 may be knit in the same way as row 404. [0062] FIG. 5 depicts a flow diagram of an example method 500 of manufacturing an article of footwear having an upper such as the upper 110. In example aspects, the method 500 includes knitting on a knitting machine, which may be a weft knitting machine, such as a flat knitting machine or a circular weft knitting machine. In one example, the knitting machine is a v-bed flat knitting machine with two needle beds, and one or more carriers, each with one or more feeders, that move across the needle beds to feed yarns to select needles in the needle beds. [0063] At a step 510, a knit textile is formed on the knitting machine. The knit textile may be intended for incorporation into an upper (e.g., upper 110) so that the knit textile may extend through a forefoot region (e.g., forefoot region 114), a midfoot region (midfoot region 116), a heel region (e.g., heel region 118), a medial side (e.g., medial side 120), and a lateral side (e.g., lateral side 122). The knit textile has an outer-facing surface (e.g., outer-facing surface 111) and an inner-facing surface (e.g., inner-facing surface 113). Step 510 includes knitting a first area at step 520 and knitting a second area at step 530.
[0064] At step 520, the first area of the upper is knit on a first needle bed and a second needle bed of the knitting machine. The first area may extend through at least the forefoot region and a throat area in the midfoot region. The first area may extend at least partially in the medial side and the lateral side. Knitting the first area of the textile at step 520 may include knitting with a first high- melting yarn (e.g., high-tenacity yarn) and a first low-melting yarn, which may have the first TPE composition discussed above with regards to the first area 131). Unless otherwise indicated, the first area knit at step 520 may have the same configuration as the first area 131, and all such features are not repeated here for brevity. [0065] At step 530, the second area of the upper is knit only on the first needle bed and extends through at least the midfoot region and the heel region on the lateral side. In some aspects, the first needle bed is a rear needle bed. The second area extends directly adjacent the first area through at least part of the midfoot region. Step 530 may be knit in accordance with the stitch diagram in FIG.4. Additionally, the second area knit at step 530 may include a second high-melting yarn, and a second low-melting yarn, which may have a second TPE composition as described previously with respect to the second area 132, where the first TPE composition from the first area may be substantially excluded from the second area. The second area 132 may be knit to extend from the first area to a biteline (e.g., biteline 117) where the upper is secured to a sole structure (e.g., sole structure 112). Unless otherwise indicated, the second area knit at step 530 may have the same configuration as second area 132, and all such features are not repeated here for brevity. [0066] Due at least in part to different knit constructions and/or yarns knit at steps 520 and 530, the first area and the second area may be formed with different thicknesses. Particularly, the first area may have a first thickness (e.g., first thickness 301) between the outer-facing surface and the inner-facing surface that is greater than a second thickness (e.g., second thickness 302) of the second area 132 between the outer-facing surface and the inner-facing surface. In one example, the second thickness may be about one-third the first thickness. [0067] Additional steps may include knitting the first area 131 and the second area 132 with separate knit feeders and joining the first area 131 with the second area 132 through intarsia. Intarsia uses separate feeders to knit separate sections of wales across the same course, which allows isolation of separate yarns to separate sections of wales in the same course. For example, one yarn carrier, which may include multiple feeders for separate yarns such as the first high-melting yarn and the first low-melting yarn, generally only traverses across a set of needles intended to be used to form the first area, while a second yarn carrier, which may include multiple feeders for separate yarns such as the second high-melting yarn and the second low-melting yarn, generally only traverses across a different
set of needles intended to be used to form the second area. The two areas may be joined through a variety of ways. In some aspects, the first set of needles used for knitting the first area in step 520 has overlap with the second set of needles used for knitting the second area in step 530. In one example, there is a two-needle overlap between the first and second sets of needles. In another example, there is a one-needle overlap. In other examples, tuck stitches are formed between the first and second areas instead of a needle overlap. Through intarsia, a course may extend across the first and second areas while the yarns in these areas may be substantially contained within the respective areas. [0068] Additional steps of the method 500 may also include knitting a third area (e.g., third area 133) of the knit textile on the first needle bed only, where the third area may extend through the midfoot region and the heel region on the medial side of the upper and extend directly adjacent the first area in at least part of the midfoot region. Additional steps may include forming a third area with a third thickness (e.g., third thickness 303) between the outer-facing surface and the inner-facing surface, which may be the same as the second thickness. Additional steps may include knitting a fourth area (e.g., fourth area 134) on the first needle bed and the second needle, where the fourth area extends into the heel region and around the ankle opening. Unless otherwise indicated, the third area and/or fourth area knit in some aspects of method 500 may have the same configuration as the third area 133 and the fourth area 134, respectively, and all such features of the respective areas are not repeated here for brevity. Additionally, method 500 may include knitting a fifth area (e.g., fifth area 135) and/or a sixth area (e.g., sixth area 136), and such features of those respective areas may apply to method 500 without being repeated here. [0069] Additional steps of method 500 may include stretching the knit textile after knitting and applying heat. Stretching the knit textile may be done on a jig, and may create more open knit structures than the knit textile had prior to stretching. Applying heat, through steaming and/or a heat press for example, may cause thermoplastic materials to melt so that the knit textile may retain the stretched configuration upon cooling. [0070] Some aspects of method 500 include applying heat and/or pressure, either as part of the above process to retain stretch or, in a later process, to thermoform at least the first area of the knit textile. In some examples, at least the first area of the knit textile is heated to a temperature within a range of about 120 degrees Celsius and 150 degrees Celsius. In one example, the first area is heated to a temperature about 135 degrees Celsius. This temperature may be sufficient to at least partially melt the first TPE composition of the first low-melting yarn so that the first TPE composition may reflow to fill in spaces in the knit structure across the outer-facing surface. In this way, a skin comprising the first TPE composition may be formed. In some aspects, heat and/or pressure is also
applied to the second area but the yarns of the second area may have higher melting temperatures than the first TPE composition such that the yarns of the second area may not melt at all or to the same extent as the first low-melting yarn. [0071] At least after thermoforming, the outer-facing surface may have a greater COF (providing more grip) in the first area than the second area. For example, the outer-facing surface of the knit textile may have a first COF in at least the first area and a second COF in at least the second area, where the first COF is greater than the second COF. [0072] Additional aspects of method 500 may include applying one or more additional components to the knit textile, such as a separate skin, to at least part of the second area and/or third area. Additionally, the knit textile may be formed into the shape of the upper, which may include joining one or more edges of the knit textile to form a seam. The method 500 may also include securing the upper to one or more sole structures. [0073] Aspects of the present disclosure have been described with the intent to be illustrative rather than restrictive. Alternative aspects will become apparent to those skilled in the art that do not depart from its scope. A skilled artisan may develop alternative means of implementing the aforementioned improvements without departing from the scope of the present disclosure. [0074] It will be understood that certain features and sub-combinations are of utility and may be employed without reference to other features and sub-combinations and are contemplated within the scope of the claims. Not all steps listed in the various figures need be carried out in the specific order described. [0075] Clause 1. An article of footwear comprising: an upper, comprising: a knit textile forming at least part of a forefoot region, a midfoot region, a heel region, a lateral side, and a medial side of the upper, the knit textile comprising an outer-facing surface and an inner-facing surface; a first area of the knit textile comprising a first thickness measured between the outer-facing surface and the inner- facing surface, the first area extending through at least part of the forefoot region, through at least part of a throat area located in the midfoot region, and through at least part of the medial side and at least part of the lateral side; and a second area of the knit textile having a second thickness measured between the outer-facing surface and the inner-facing surface, wherein the second thickness is less than the first thickness, the second area extending through at least part of the midfoot region and through at least part of the heel region on the lateral side of the upper, and the second area extending adjacent to the first area in at least the midfoot region.
[0076] Clause 2. The article of footwear of clause 1, wherein at least a portion of the first area has a double knit construction that comprises a high-tenacity yarn and a yarn comprising a thermoplastic elastomer. [0077] Clause 3. The article of footwear of any of clauses 1-2, wherein at least a portion of the second area has a single knit construction comprising a high-tenacity yarn. [0078] Clause 4. The article of footwear of any of clauses 1-3, wherein the knit textile further comprises a third area extending through at least part of the midfoot region and through at least part of the heel region on the medial side of the upper, the third area extending adjacent to the first area in at least the midfoot region, wherein the knit textile has a third thickness in the third area measured between the outer-facing surface and the inner-facing surface, wherein the third thickness is less than the first thickness. [0079] Clause 5. The article of footwear of clause 4, wherein the knit textile further comprises a fourth area extending at least partially around an ankle opening, wherein the fourth area comprises a fourth thickness that is greater than the second thickness. [0080] Clause 6. The article of footwear of any of clauses 1-5, wherein the second area extends from the first area to a biteline where the upper is secured to a sole structure. [0081] Clause 7. The article of footwear of any of clauses 1-6, wherein the outer-facing surface of the knit textile has a first coefficient of friction in at least the first area and a second coefficient of friction in at least the second area, the first coefficient of friction being greater than the second coefficient of friction. [0082] Clause 8. The article of footwear of any of clauses 1-7, wherein the second thickness is about one-third of the first thickness. [0083] Clause 9. An article of footwear comprising: an upper, comprising: a knit textile forming at least part of a forefoot region, a midfoot region, a heel region, a lateral side, and a medial side of the upper, the knit textile comprising an outer-facing surface and an inner-facing surface; a first area of the knit textile extending through at least part of the forefoot region and through at least part of a throat area in the midfoot region, and extending at least partially through the medial side and the lateral side; and a second area of the knit textile having a different knit construction than the first area and extending through at least part of the midfoot region and through at least part of the heel region on the lateral side of the upper, and extending adjacent to the first area through at least the midfoot region, wherein the outer-facing surface of the knit textile has a first coefficient of friction in at least the first area and has a second coefficient of friction in at least the second area, the first coefficient of friction being greater than the second coefficient of friction.
[0084] Clause 10. The article of footwear of clause 9, wherein the first area has a double knit construction, and the second area has a single knit construction. [0085] Clause 11. The article of footwear of any of clauses 9-10, wherein the first area comprises a high-tenacity yarn and a yarn comprising a thermoplastic elastomer. [0086] Clause 12. The article of footwear of clause 11, wherein the outer-facing surface comprises a skin that comprises the thermoplastic elastomer. [0087] Clause 13. The article of footwear of any of clauses 11-12, wherein the thermoplastic elastomer is absent from the second area. [0088] Clause 14. The article of footwear of any of clauses 9-13, wherein the first area has a greater knit density than the second area. [0089] Clause 15. An article of footwear comprising: an upper, comprising: a knit textile extending at least partially through a forefoot region, a midfoot region, a heel region, a lateral side, and a medial side of the upper, the knit textile comprising an outer-facing surface and an inner-facing surface; a first area of the knit textile comprising a first thickness measured between the outer-facing surface and the inner-facing surface; and a second area of the knit textile comprising a second thickness measured between the outer-facing surface and the inner-facing surface, wherein the second thickness is less than the first thickness, wherein the first area has a first stiffness and the second area has a second stiffness, the second stiffness being greater than the first stiffness. [0090] Clause 16. The article of footwear of clause 15, wherein the second area is contiguous with the first area. [0091] Clause 17. The article of footwear of any of clauses 15-16, wherein a translucency of the second area is greater than a translucency of the first area. [0092] Clause 18. The article of footwear of any of clauses 15-17, wherein the first area comprises a thermoformed network of yarns comprising a thermoplastic elastomer that is softened and solidified. [0093] Clause 19. The article of footwear of clause 18, wherein the thermoplastic elastomer forms a film at least partially covering the outer-facing surface of the knit textile in the first area. [0094] Clause 20. The article of footwear of any of clauses 15-19, wherein the outer-facing surface of the knit textile has a first coefficient of friction in at least the first area and has a second coefficient of friction in at least the second area, the first coefficient of friction being greater than the second coefficient of friction.