Article of Footwear with Integrally-Knitted Upper and Sole Including Grip Yarn and Method of Manufacturing

This application is a divisional of United Stated Nonprovisional application Ser. No. 18/522,538, filed Nov. 29, 2023, which claims the benefit of priority to U.S. Provisional Application No. 63/429,211, filed Dec. 1, 2022, and both of which are hereby incorporated by reference in their entirety.

The present disclosure generally relates to an article of footwear that includes an integrally-knitted footwear upper and sole, the sole including a grip yarn, and to a method of manufacturing the article of footwear.

Footwear typically includes a sole configured to be located under a wearer's foot and an upper attached to the sole. The upper typically surrounds the sides and top of the foot. The sole is often several layers, including an insole, a midsole and an outsole, and typically functions to provide cushioning and impact protection. Donning footwear may be difficult for some wearers, such as those with limited dexterity and young children.

Articles of footwear disclosed herein provide a simplified construction with an integrally-knitted upper and sole (i.e., a knit upper and a knit sole that are knitted together). The sole is relatively thin to enable the wearer's foot to feel the ground underneath the sole to a greater extent than would a traditional sole structure that includes a foam midsole, for example. Integrating grip yarns below the foot enables the sole to provide both the footbed and the traction and durability functions of an outsole while eliminating the need for a typical midsole and insole. Although the article of footwear may be implemented in all sizes, this may aid early development and walking for toddlers. Additionally, the knit construction may advance sustainability initiatives as waste and post processing are minimal. The article of footwear may be especially useful for toddlers, young children, and those with limited dexterity, as it may enable them to independently don and doff their footwear.

The present disclosure generally relates to an article of footwear that includes an integrally-knitted footwear upper and sole, the sole including reflowed polymeric material of a grip yarn. For example, the ground contact surface of the sole may include the reflowed polymeric material. In an aspect, the footwear upper and the sole are a one-piece, unitary knit construction.

In one example, the grip yarn may include a core and a sheath, and the sheath may include thermoplastic material that reflows (e.g., is thermally processed to at least partially melt, and then subsequently cools and resolidifies) to form the polymeric material that may form at least a portion of the ground contact surface. In some implementations, the sole may include more than one grip yarn, e.g., grip yarns of different materials, and the reflowed polymeric material may be a polymeric composition of the different grip yarns.

In an example, the reflowed polymeric material of the sole may be at an outer layer of the sole, and the sole may further include an inner layer integrally knit with the outer layer. The inner layer may be a different yarn than the grip yarns, and may establish a footbed having a foot contact surface. For example, the yarn of the inner layer may include chenille yarn.

In an aspect, the footwear upper may include a knitted medial quarter at a medial side of the article of footwear, a knitted lateral quarter at a lateral side of the article of footwear, a knitted tongue secured to the knitted medial quarter, and a knitted heel portion extending between the knitted medial quarter and the knitted lateral quarter at a rear of the article of footwear. The sole and the footwear upper may together define a foot-receiving cavity, and the knitted medial quarter, the knitted lateral quarter, the knitted tongue, and the knitted heel portion may together define an ankle opening at the foot-receiving cavity. The knitted lateral quarter may extend to form a strap configured to cross over the knitted tongue and secure at the knitted medial quarter to secure a foot within the foot-receiving cavity.

In an example, an article of footwear disclosed herein comprises an integrally-knitted footwear upper including an underfoot portion and defining a foot-receiving cavity above the underfoot portion. The footwear upper includes a knitted medial quarter at a medial side of the article of footwear, a knitted lateral quarter at a lateral side of the article of footwear, a knitted tongue secured to the knitted medial quarter, and a knitted heel portion extending between the knitted medial quarter and the knitted lateral quarter at a rear of the article of footwear. The article of footwear further includes a sole secured to an exterior surface of the underfoot portion. The knitted medial quarter, the knitted lateral quarter, the knitted tongue, and the knitted heel portion together define an ankle opening at the foot-receiving cavity. The knitted lateral quarter extends to form a strap configured to cross over the knitted tongue and secure at the knitted medial quarter to secure a foot within the foot-receiving cavity.

In an implementation, an article of footwear may comprise a knitted component forming one or more of an overfoot portion of the footwear and an underfoot portion of the footwear. The underfoot portion comprises an external facing layer forming ground contacting portions and an internal facing layer forming foot contacting portions. The external facing layer includes a first material comprising a thermoplastic material and the internal facing layer including a second material different from the first material. One or more portions of the external facing layer including the first material have a different coefficient of friction relative to the internal facing layer including the second material.

In an aspect, the one or more portions of the external facing layer have a greater coefficient of friction relative to the internal facing layer including the second material.

In an example, the underfoot portion may include one or more intersection portions at or near a junction of the external facing layer and the internal facing layer that include the first material.

In a further example, the external facing layer may comprise one or more raised traction elements including the first material. The one or more raised traction elements may include reflowed first material.

The external facing layer may comprise one or more interlooped yarns. Each of the one or more interlooped yarns may have a coating of the first material surrounding a core yarn. The core yarn may have a second material that excludes the thermoplastic material and has a greater melting temperature than the first material. In an aspect, the first material may be at least partially fused with one or more core yarns. The internal facing layer may comprise one or more second interlooped yarns comprising the second material. The first material may be at least partially fused to a portion of the one or more second interlooped yarns.

An article of footwear may comprise an integrally-knitted footwear upper and sole. The sole may include one or more interlooped yarns comprising a first material. The first material may include a thermoplastic material.

In an aspect, the sole may include reflowed polymeric material of the thermoplastic material. For example, a ground contact surface of the sole may include the reflowed polymeric material.

In some implementations, at least one of the one or more interlooped yarns includes a core and a sheath, and the sheath includes the thermoplastic material.

In an example, the one or more interlooped yarns comprising the first material is a first yarn, the one or more interlooped yarns include a second yarn comprising a second thermoplastic material, and a ground contact surface of the sole is a polymeric composition of reflowed polymeric material of the first yarn and reflowed polymeric material of the second yarn.

In a further example, the one or more interlooped yarns comprising the first material may be at an outer layer of the sole, and the sole may further include an inner layer integrally knit with the outer layer. The inner layer may include a yarn comprising a different material than the first material and may establish a footbed having a foot contact surface. For example, a ground contact surface of the sole may include reflowed polymeric material of the thermoplastic material, and one or more portions of the of the ground contact surface including the reflowed polymeric material may have a different coefficient of friction relative to the foot contact surface including the yarn of the inner layer. In the same example or in a different example, the yarn of the inner layer establishing the footbed may include two or more twisted core yarns with cut pile yarns between the twisted core yarns.

A method of manufacturing an article of footwear disclosed herein comprises integrally knitting a footwear upper and a sole of an article of footwear, the sole including a grip yarn. The method further includes thermoforming the grip yarn such that the sole includes reflowed polymeric material of the grip yarn. As used herein, “thermoforming” is a thermal process involving heating and shaping a thermoplastic material.

The above features and advantages and other features and advantages of the present teachings are readily apparent from the following detailed description of the modes for carrying out the present teachings when taken in connection with the accompanying drawings. It should be understood that even though in the following Figures embodiments may be separately described, single features thereof may be combined to additional embodiments.

Referring to the drawings, wherein like reference numbers refer to like components throughout the views,show an article of footwearthat includes an integrally-knitted footwear upperand sole. The integrally-knitted footwear upperand solemay be referred to as an upper portion and a sole portion, or as an overfoot portion and an underfoot portion, respectively, of the one-piece article of footwear, as they are contiguous and knitted together with one another as a one-piece component. Stated differently, the footwear upperis a knitted construction, the soleis also a knitted construction, and the footwear upperand the soleare knitted together as a one-piece, unitary knit construction. The footwear upperand the solemay be formed as an integral one-piece element during a single knitting process, such as a weft knitting process (e.g., with a flat knitting machine or circular knitting machine), a warp knitting process, or any other suitable knitting process. That is, the knitting process on the knitting machine may substantially form the knit structure of the footwear upperand the solewithout the need for additional knitting steps. Alternatively, in other embodiments, two or more portions of the footwear upperand the solemay be formed separately as distinct integral one-piece elements and then the respective elements attached. Accordingly, as utilized herein, an article of footwear is defined as being formed of and having a “unitary knit construction” when formed as a one-piece element through a knitting process. Portions of the knit article of footwearcan be joined to each other following the knitting process (e.g., edges of the knitted footwear uppercan be joined to one another, as at a seam). In various aspects, other elements (e.g., logos, trademarks, placards) can be added following the knitting process.

Moreover, the knitted soledescribed herein comprises the entire sole structure of the article of footwear, as the article of footwearmay be characterized by the absence of any additional sole layers or sole components, such as the absence of a midsole, an insole, a strobel, etc. As such, the knitted solemay comprise both a ground contact surface(e.g., an exterior, exposed, ground-engaging surface, also referred to as ground-contacting portions) and a foot-contact surface(e.g., an interior foot-receiving surface on which the foot rests, also referred to as foot-contacting portions, best shown in). The knitted soleis thus multi-functional while maintaining a lightweight and thin construction which may be especially advantageous for developing toddlers. As discussed herein, the knitted soleachieves this multifunctionality in part by utilizing a grip yarn, shown best in, and having a ground contact surfaceof a polymeric compositionthat includes a reflowed thermoplastic materialof the grip yarn, best shown in.

With reference to, the article of footwearas well as the upperand the solemay be divided into a forefoot region, a midfoot region, and a heel region. The forefoot regiongenerally includes portions of the article of footwearcorresponding with the toes and the metatarsophalangeal joints (which may be referred to as MPT or MPJ joints) connecting the metatarsal bones of the foot and the proximal phalanges of the toes. A forward portion of the forefoot regionmay thus be referred to as a toe region. The midfoot regiongenerally includes portions of the article of footwearcorresponding with the arch area and instep of the foot, and the heel regioncorresponds with rear portions of the foot, including the calcaneus bone. The forefoot region, the midfoot region, and the heel regionare not intended to demarcate precise areas of the article of footwearbut are instead intended to represent general areas of the article of footwearto aid in the following discussion.

The article of footwearhas a lateral side(indicated in) and a medial side(indicated in). The lateral sideand the medial sideextend through each of the forefoot region, the midfoot region, and the heel region, and correspond with opposite sides of the article of footwear, each falling on an opposite side of a longitudinal midline (LM) of the article of footwear, indicated in. The lateral sideis thus considered to be opposite from the medial side. The article of footwearas shown is configured for a right foot. An article of footwear configured for a left foot may be a mirror image of the article of footwear.

The footwear upperincludes various portions or zones including a knitted medial quarterat the medial sideof the article of footwear, a knitted lateral quarterat the lateral sideof the article of footwear, a knitted tonguesecured to the knitted medial quarter, a knitted heel portionextending between the knitted medial quarterand the knitted lateral quarterat a rearof the article of footwear, a knitted toe boxat a frontof the article of footwear, a knitted collar, and a knitted heel pull. The knitted heel pullextends integrally from the knitted collar. In the embodiment shown, the knitted heel pullis configured as a strap having an end portionsecured to the knitted collar, such as by stitching, to form a loop. In other embodiments, the knitted heel pullmay simply be a tab rather than a loop, or there may be no heel pull. The knitted heel pullmay be gripped to help pull the article of footwearover the foot when inserting the foot into the foot-receiving cavity.

The various zones or parts of the zones of the footwear upperand of the solemay be knitted of different yarns or different combinations of yarns than one another as discussed herein. In, boundaries between portions of the article of footwearthat are comprised of different yarns or combinations of yarns than one or more bordering portions are indicated with phantom lines. A boundary Bis indicated between the soleand the upper. A boundary Bis indicated bordering a top or rear edge of the toe box, such as between the tongueand the toe box. A boundary Bis indicated between the yarns in a forward portion of the lateral quarteradjacent to the toe boxand yarns of the remainder of the lateral quarter. The yarns of the forward portion of the lateral quarterbounded by boundary Bare near a forward lower edge of the lateral quarterand are contiguous with and may be the same as the yarns of the toe box, as discussed herein. A boundary Bis indicated between the knitted collarand the heel portion. A boundary Bis indicated between the knitted collarand the heel pull. A boundary Bis indicated between the peripheral region of the lateral quarterand strapand the remainder of the lateral quarterand strapas the peripheral region may be of another yarn or yarns than the remainder as discussed herein. A boundary Bis indicated between a peripheral region at the top of the tongueand the remainder of the tongueas the peripheral region at the top of the tonguemay be a different yarn or yarns than the remainder of the tongue, as discussed herein. A boundary Bis indicated between the heel regionand the lateral quarter. A boundary Bis indicated between the heel regionand the medial lateral quarter.

As used herein, the term “yarn” is understood to refer to a long or essentially continuous strand of fibers or filament(s) in a form suitable for knitting. Types of yarns include continuous filament yarns, examples of which include monofilament yarns (consisting of a single continuous filament) and multi-filament yarns (consisting of a plurality of flat or textured filaments which are typically twisted or air-entangled with each other). Spun yarns are another type of yarn, which consist of a plurality of staple fibers (such as cotton or wool fibers) or cut fibers or filaments which are entangled with each other in the spinning process. Complex yarns are yet another type of yarn, which may consist of a cord or cabled yarn, or which may consist of two or more single yarn strands combined into a ply yarn. Natural fibers or filaments may be used, including naturally-occurring cellulosic fibers such as cotton or flax, naturally-occurring protein-based fibers or filaments such as wool or silk, and naturally-occurring mineral-based materials such as asbestos. Man-made fibers or filaments may be used, including man-made fibers or filaments made from inorganic materials such as glass or metals, as well as fibers or filaments made from regenerated natural polymers, including cellulose-based polymers and protein-based polymers, man-made carbon fibers or filaments, and man-made fibers or filaments made from synthetic polymers. In many cases, the synthetic polymers are thermoplastics, including thermoplastic elastomers, although thermosets such as elastane may also be used. Synthetic polymers commonly used to make fibers or filaments include polyesters (such as polyethylene terephthalate (PET)), polyamides (such as Nylon-6, Nylon 6,6, and Nylon-11), polyolefins (such as propylene homopolymers and copolymers, as well as ethylene homopolymers and copolymers), and polyacetates (such as cellulose acetate fibers). Polyurethanes, such as thermoplastic polyurethanes, may also be used to make fibers or filaments. The strands may comprise or consist of yarn including natural fibers or filaments, man-made fibers or filaments, or a combination of both natural and man-made fibers or filaments, such as a spun yarn comprising a blend of cotton and polyester fibers. The strands may comprise or consist of a multi-filament yarn comprising polyester or polyamide filaments, such as a commercially available embroidery thread.

Generally, industrial knitting machines and other industrial-scale manufacturing processes require the use of yarns having a minimum tenacity of about 1.5 grams per denier. Tenacity refers to the amount of force needed to break a yarn divided by the linear mass density of the yarn and is determined by subjecting a sample of the yarn to a known amount of force until the sample breaks, for example, using a strain gauge load cell. Within the scope of the disclosure, yarns having tenacities greater than about 5 grams per denier are considered to be high tenacity yarns. High-tenacity yarns may include fibers or filaments comprising polymer(s) such as aramids and ultra-high molecular weight polyethelene (UHMWPE). The yarns used in accordance with the present disclosure can be lower tenacity yarns, high tenacity yarns, or any combination thereof. In some examples, the strands may comprise or consist of a spun yarn, a mono-filament yarn, or a multi-filament yarn having a tenacity of at least 1.5 grams per denier, or of at least 2.5 grams per denier. In other examples, the strands may comprise or consist of a multi-filament yarn having a tenacity of at least 11 grams per denier.

The soleand the footwear uppertogether define a foot-receiving cavity, which is shown partially exposed inand more exposed in. The knitted medial quarter, the knitted lateral quarter, the knitted tongue, and the knitted heel portiontogether define an ankle openingat the foot-receiving cavity. The knitted collarextends along the knitted medial quarter, along the knitted lateral quarter, and along the knitted heel portionat the ankle openingand further defines the ankle opening.

As best shown in, the knitted tonguehas a medial edgeextending from the toe regionof the article of footwearto the ankle openingat the medial sideand stitched to the knitted medial quarterfrom the toe regionto the ankle opening. As shown, the medial edgeis stitched to an edgeof the knitted medial quarter. In other embodiments, the medial edgemay be stitched to the medial quarteronly partway to the ankle openingin order to provide the ability to open the foot-receiving cavityto a greater extent at the medial sidewhen inserting the foot. In still other embodiments, the entire medial edgemay be unstitched and unsecured to the medial quarter.

The knitted tonguehas a lateral edgeextending from the toe regionto the ankle openingat the lateral side. The knitted tongueand the knitted lateral quarterare unstitched and separable from one another at the lateral edgeto expand the ankle openingto ease entry into the foot-receiving cavity. For example, in, the knitted tonguemay be gripped at or near a rear lateral cornerand lifted forward and to the medial side(e.g., across the longitudinal midline (LM)) to further expose the foot-receiving cavity.shows the knitted tonguemoved to this open position, revealing more of the foot-receiving cavity.

The footwear upperhas a knitted toe boxforward of the knitted tongue. Specifically, the knitted toe boxextends between the knitted tongueand the solein the toe regionand is adjacent to a forward extentof the knitted tongue. The forward extentof the knitted tongueis the same as, and is coincident with, the boundary B.

The knitted lateral quarterextends to form a strap. The strapis an integral portion of the knitted lateral quarter. As is evident in, the knitted lateral quarterextends from the toe regionto the heel regionof the article of footwearand tapers in width from a proximal endof the knitted lateral quarterat the soleto a distal endof the strap. The strapis configured to cross over the knitted tongueand secure at the knitted medial quarterto secure a foot within the foot-receiving cavity. More specifically, the tapered shape of the strapalong with its length from the proximal endto the distal endenables it to be manipulated once the foot is fully inserted in the foot-receiving cavityby moving the distal endto the medial sideso that the strapcrosses over the knitted tongueand secures at the knitted medial quarterto secure the foot within the foot-receiving cavity.

Referring to, the straphas a first fastener portionsecured to an inner side(also referred to as an inner surface) of the strap, and the medial quarterhas a second fastener portionat an outer side(also referred to as an outer surface) of the medial quarter. In the embodiment shown, the first fastener portionand the second fastener portiontogether comprise a hook-and-loop fastener. One of the first fastener portionand the second fastener portionincludes a plurality of loops and the other of the first fastener portionand the second fastener portionincludes a plurality of hooks that engage with the loops when the first fastener portionand the second fastener portionare pressed together. In the embodiment shown, the first fastener portionincludes hooksand the second fastener portionincludes loopswith which the hooksengage. Hook-and-loop fastening may be easier for young children and those with limited dexterity to manipulate than other fastener types. Suitable material with hooks and loops is available from 3M Company at 3M Center, St. Paul, Minnesota under the trade name VELCRO™.

The strapis the only strap included in the article of footwearthat secures the foot within the foot-receiving cavity. Additionally, no zippers, laces, snaps, buttons, or other securement mechanisms are present to secure the upperaround the foot. Stated differently, a single strapis used to secure the article of footwearto the foot. Additionally, the strapwraps from the lateral sideover the tongueto secure at the medial side. Alternatively, in other embodiments, the strapmay wrap from the medial sideto secure at the lateral side. In some embodiments, the footwear may be configured so that it is generally symmetrical about the longitudinal midline LM so that the wearer may choose to don the footwear with the strapwrapping from either the lateral sideto secure at the medial side, or from the medial sideto secure at the lateral side.

When donning their footwear, toddlers and young children may sit cross-legged and/or may tend to crouch down and splay their feet outward. Additionally, it may be easier for most toddlers and young children to pull toward the midline of their body (inward) than it is for them to pull away from their body (outward). In light of this, the article of footwearbeing configured with the strapwrapping from the lateral sideover the tongueto secure at the medial sidemay make it easier for toddlers and young children to secure and release the strapindependently than if the strapwrapped from the medial sideto the lateral sideand secured on the lateral side. Additionally, toddlers and young children tend to walk with their feet relatively spread apart so that it is unlikely that the location of the secured first fastener portionand second fastener portionat the medial sidewould interfere with or be a barrier to their walking mechanics.

Each of the sole, the medial quarter, the lateral quarter(including the strap), the tongue, the heel portion, the toe box, the collar, the heel pull, and the soleare knitted of a specific yarn or combination of yarns that enable the integrally-knitted, one-piece article of footwearto provide the desired traction, durability, flexibility, and other properties and characteristics with minimal waste and minimal post-processing following knitting of the article of footwear.

is a side view of the article of footwear ofturned inside out. An inner side of the knitted medial quarter, the sole, the heel portion, the collar, and a portion of the inner side of the tongueare exposed. The article of footwearis shown inprior to stitching the medial edgeof the tongueto the edgeof the knitted medial quarter. An outer side(also referred to as an outer surface) of the strapis shown in.

is an opposite side view thanwith the article of footwearturned inside out. In, an inner side of the knitted lateral quarterand strapare exposed along with the remainder of the inner side of the sole, the heel portionand the tongue. The inner sideof the strapis shown inprior to securing the fastener portionto the inner side.represent that the article of footwearis a unitary one-piece, integrally-knit component following the knitting process and before any post processing such as stitching.

The textured shading inrepresents a yarn that may be used at the inner side of one or more of the medial quarter, the sole, the heel portion, and the tonguefor added comfort against the foot of the wearer. For example, the yarn may be a multi-component yarn, such as a yarn including two or more twisted core yarns with cut pile yarns between the twisted core yarns. For purposes of discussion, such yarn may be referred to herein as chenille yarn, as discussed herein. In some embodiments, the inner sideof the lateral quarterincluding the strapmay also have the same yarn.

Referring again to, after the knitting process creates the unitary, one-piece component shown in, the medial edgeof the tongueis stitched to the edgeof the medial quarterusing stitching. The stitchingbegins atA in the toe boxforward of the edges,and progresses along the edges,to the endB of the stitchingat the ankle opening. By beginning the stitching in the toe box, the seam created by the abutting edges,is better reinforced.

In order to ensure that the strapoverlays the tongueproperly without wrinkling or bunching, following stitching of the medial quarterto the tongue, the forward edgeof the strapmay be aligned with markers or other locating features along the outer side of the tongueas it overlays the tongueto the secured position. A reinforcing box stitchmay then be applied, extending through the tongueand the lower extent of the strap.

The toe regionis contoured both from the soleto the tongueand from the medial sideto the lateral side. The toe regionmay be the most contoured portion of the article of the article of footwear. For example, the toe regionis contoured in the vertical direction as it extends from the soleunderfoot to the tongueand is contoured in the horizontal direction as it extends from the medial quarterto the lateral quarterand over the toes of the foot. More specifically, the toe regionis convex at an exterior and convex at an interior of the toe regionin both the vertical direction and the horizontal direction. In order to accommodate this curvature, the knitted toe boxmay include an elastomeric yarn adjacent to the forward extentof the knitted tongue. In one non-limiting example, the elastomeric yarn of the knitted toe boxmay be an “E04” yarn supplied by Unifi, Inc. of Greensboro, N.C., which preferably has a greater elasticity than other yarns that may be used to form the article of footwear. The E04 yarn of the knitted toe box, and other yarns referred to herein as E04 yarn, may comprise an elastane core (i.e., LYCRA© available from E.I. duPont de Nemours Company) wrapped with polyester.

Furthermore, in order to reduce the bulk of the article of footwearat the lower forward extent of the lateral quarterand promote ease in moving the strapfrom the open position to the secured position wrinkling, a lower extentA of the lateral quarterat the forward edgeincludes the same elastomeric yarn that forms the knitted toe boxand extends contiguously from the knitted toe box. The lower extentA that includes the same elastomeric yarn is indicated inand is bounded by the boundary lines Band the forward edge. The remainder of the lateral quartermay include different types of yarn or yarns that are thicker or less flexible in order to stabilize the foot over the sole. By including the lower extentA having the same flexible yarn as the toe box, the extreme contours of the toe regionare accommodated without wrinkling of the upperin the toe region.

Other portions of the article of footwearthat may benefit from a flexible and thin knitted construction afforded by elastomeric yarn include the knitted collar, the knitted heel pull, and the outer perimeterof the strapat both the forward edge, the rear edge, and the distal end. Accordingly, in the embodiment shown, each of the knitted collar, the knitted heel pull, and the outer perimeterof the strapcomprise the same or different type of elastomeric yarn as the toe box.

As further discussed with respect to, in order to reinforce at least a lower portionof the toe box, also referred to as a forward portion, the knitted toe boxmay include one or more interlooped yarns comprising a first material, the first material including a thermoplastic material. The interlooped yarns may include yarns comprising a second material having a different melting temperature than the first material. The knitted toe boxmay include reflowed polymeric material of the thermoplastic material. The second material may have a higher melting temperature than the thermoplastic material. For example, the second material may be elastomeric yarn discussed may be adjacent a forward extent of the knitted tongue and the yarn including the first material may be knitted with the elastomeric yarn of the toe box. For example, the yarn comprising the first material may include a core and a sheath, and the sheath may include thermoplastic material that reflows, as described and referred to herein as grip yarn. In some examples, the one or more interlooped yarns in the toe boxmay at least partially include a thermoplastic polymer material that transitions from a solid state to a softened or liquid state when subjected to a temperature at or above its melting point and then transitions back to the solid state when cooled. Further, in some examples, the thermoplastic polymer material may be melted, reflowed, and solidified. For example, the thermoplastic polymer material may be melted and reflowed over a desired area (e.g., a portion of the toe boxsuch as the lower portion) by applying one or more of heat (e.g., temperature at or above the melting temperature of the thermoplastic polymer material) and pressure. After reflowing, the knitted component (e.g., the integrally-knitted footwear upper) may be cooled to solidify the reflowed thermoplastic polymer. As a result, the desired area (e.g., the lower portion) includes the reflowed and solidified thermoplastic polymer. In one example, the reflowed and solidified material may form a film (also referred to as a skin) over the desired area of the knitted component (e.g., the lower portionof the toe boxmentioned above). The film may increase durability, abrasion resistance, and weatherization. In another example, the thermoplastic polymer material may be softened and cooled. For example, one or more of a temperature, a pressure, and time of application of heat and/or pressure may be adjusted to soften the thermoplastic material without melting. As a result, the softened thermoplastic polymer may have a higher viscosity compared to the melted thermoplastic material. The softened thermoplastic polymer may spread to adjacent knitted portions (e.g., knitted portions comprising the second material) and join the knitted portions, thereby providing additional strength.

In one example, one or more interlooped yarns may include a core and a sheath, where the sheath includes the thermoplastic polymer material. In some examples, the one or more interlooped yarns comprising the thermoplastic polymer may be a coated yarn (e.g., core coated with sheath, the sheath comprising the thermoplastic polymer material), a monofilament yarn, a bicomponent monofilament yarn (e.g., a thermoplastic polymer co-extruded with another thermoplastic polymer in a core and sheath, or side-by-side configuration), or a multifilament yarn. Examples of thermoplastic polymer materials include but not limited to thermoplastic elastomers, polyamides, polyesters, polyurethane, and polyolefins.

After the article of footwearis knitted and sewn to form the foot-receiving cavity, in a post-processing step described herein, the grip yarn at the lower portionof the toe boxmay be thermoformed to reflow and form a reinforcing skinat the lower portionof the knitted toe boxadjacent to the sole.

is a cross-sectional view of the article of footwearoftaken at lines-in.depicts the solehaving an outer layerand an inner layer. The outer layermay also be referred to as an external facing layer, and the inner layermay also be referred to as an internal facing layer. It is to be understood that the outer layerand the inner layerare integrally knitted with one another but include at least one different yarn than one another. For example, the outer layerof the soleincludes one or more grip yarns.