Footwear Article with Improved Bonding Between Upper and Sole

This application claims the priority benefit of U.S. Provisional Patent Application No. 63/627,796 (filed on Jan. 31, 2024), which is hereby incorporated herein by reference in its entirety.

The present disclosure generally relates to a footwear article with improved bonding strength between a footwear upper and a sole structure.

The design and manufacture of footwear and sporting equipment involves a variety of factors from the aesthetic examples, to the comfort and feel, to the performance and durability. While design and fashion may be rapidly changing, the demand for increasing performance in the footwear and sporting equipment market is unchanging. In addition, the market has shifted to demand lower-cost and recyclable materials still capable of meeting increasing performance demands. To balance these demands, designers of footwear and sporting equipment employ a variety of materials and designs for the various components.

The present disclosure is related to a footwear article (and method of making a footwear article) associated with improved bonding (e.g., reduced likelihood of delamination) between a footwear upper and a sole structure and along at least a portion of the biteline. For example, the footwear upper can include an outer-facing surface (e.g., externally-facing side) that faces away from the foot-receiving cavity. In addition, the outer-facing surface can include a first zone that overlaps with, and is bonded to, the sole structure (e.g., a plate or midsole or outsole or other portion of the sole structure) and a second zone that does not overlap with the sole structure (e.g., at least part of the second zone includes portions of the upper that enclose the foot-receiving space, such as the quarter(s), instep, vamp, heel, etc.). Examples of the present disclosure are directed to various features of the first zone that improve bonding to the sole structure (and that might not be present in the second zone or that might be different in the second zone), such as bonding via thermal bonding, adhesive bonding, mechanical bonding, chemical bonding, and the like. In at least some examples, the bonding between the first zone of the upper and the sole structure can include a bond that arises from the sole being molded directly onto the upper, such that the material of the sole and/or the material of the first zone are (due to heat) at least partially softened (e.g., can be melted) and fused to one another (e.g., the materials can at least partially mix in a softened state and solidify in a comingled state to form the bond). This is one example of bonding, and the properties of the first zone can improve bonding to the sole structure via one or more other types of bonding methods (e.g., mechanical, chemical, adhesive, etc.).

A footwear upper can include a material (e.g., synthetic leather material) having properties (e.g., chemical composition) that are configured to bond with a sole structure. For example, the sole structure can include a first thermoplastic composition and the footwear-upper material can include a second thermoplastic composition, which is configured to bond with the first thermoplastic composition (e.g., via a thermal bond) and resists delamination when subjected to forces associated with a user wearing the footwear article during athletic-related activities. Conventional techniques often include applying additional or different properties (e.g., surface properties, including surface chemical composition) to the footwear-upper material (e.g., the first zone and the second zone), such as by applying cleaning agents, corona treatment, printed components (e.g., ink or other colorant carriers), surface texture (e.g., surface with varied relief or other z-height dimensional offset), and the like. However, it has been discovered in association with this present disclosure that these additional and/or different properties of the footwear-upper material can (e.g., when associated with the first zone that overlaps with the sole structure) reduce the strength of the bond between the footwear-upper material and the sole structure. For example, if the first zone of the upper that overlaps with the sole structure includes a surface chemistry that is different from the sole structure, then a bond between the two structures might not be as strong and might have a higher risk of delamination (e.g., might have a lower peel strength based on a peel strength test).

In contrast to conventional approaches, examples of the present disclosure can include the first zone of the outer-facing surface (e.g., that overlaps with, and is bonded to, the sole structure) having different properties as compared to the second zone of the outer-facing surface (e.g., that does not overlap with the sole structure). The properties of the first zone that are different from the properties of the second zone can improve the bond strength between the first zone and the sole. For example, the first zone can include, on the outermost surface of the outer-facing surface, a first property, and the first property is different from a second property, which is on the outermost surface of the outer-facing surface in the second zone. The first property and the second property can include, among other things, a chemical composition (e.g., surface chemistry, which can include a thermoplastic composition), a surface texture (or lack thereof), or a combination thereof, or any other surface property that might differ. In some examples, the first property and second property are respective chemical compositions, and the first property includes a thermoplastic polyolefin resin composition, which is different from the second property. For instance, the surface in the second zone might not include any amount of the thermoplastic polyolefin resin composition, or might include less than some threshold amount (e.g., less than 5% percentage composition, such as by weight). In some examples, the second property can include (on a surface in the second zone and in contrast to the surface in the first zone) a cleaning-solution composition, a more oxidized surface, a primer composition, an ink composition, a surface texture (e.g., deeper relief features as compared to the first zone), or any and all combinations thereof. In examples, the first property (e.g., the thermoplastic composition on the surface of the first zone) can contribute to improved bond strength between the footwear upper and the sole structure.

The first zone (e.g., with properties that are different from the second zone and that contribute to improved bonding with the sole) can include a width that extends from a terminal edge of the upper (e.g., the terminal edge that is at least partially wrapped beneath the footbed) to a position aligned with a biteline (e.g., the position or juncture at which a terminal edge of the sole structure aligns with the upper where the two are bonded to one another). In at least some examples, the width can vary depending on a position of the first zone around the periphery of the footwear article. For example, a first width of the first zone along the midfoot can differ from a second width of the first zone in the forefoot. In some examples, the varied widths associated with the first zone can contribute to enhanced strength in select areas (e.g., where the width is larger) and reduced weight in other areas (e.g., where the width is smaller), and in this respect, the varied widths can contribute to balancing of various overall (and sometimes competing or conflicting) properties. That is, at some positions, the first zone can include a larger width where increased bond strength is desired between the upper and other underfoot structures (e.g., the sole, lasting board, strobel, etc.), whereas in other positions the first zone can include a smaller width where sufficient bond strength can be achieved with less bonding surface area and the smaller width can contribute to less overall materials and a lower overall weight (of the footwear article).

In at least some examples, the outer-facing surface can include a transition zone that is positioned between the first zone and the second zone. For example, the upper can include the first zone that is adjacent to the transition zone, which is adjacent to the second zone. In examples, the outermost surface of the transition zone is not bonded to the sole structure. For example, the transition zone can extend from the biteline and to the second zone (e.g., to a position at which the outer-facing surface transitions from having the first property to having the second property). In addition, the transition zone can include properties that can contribute to a stronger bond with the sole structure (e.g., a chemical composition, a surface texture (or lack thereof), or a combination thereof, or any other surface property) and that are similar to the first zone and that are different from the second zone. In examples, the transition zone can include (or form) a buffer zone that safeguards against properties of the second zone being associated with a surface bonded to the sole structure, and in this respect, the buffer zone can reduce the likelihood of bonding failure and delamination between the upper (in the first zone) and the sole structure. In at least some instances, the transition zone can extend around the entire periphery of the footwear article. In some examples, a width of the transition zone (e.g., from the biteline to the second zone) is the same at two or more positions around the periphery. In some examples, a width of the transition zone (e.g., from the biteline to the second zone) can vary depending on a position around the periphery.

Surface chemistry can be assessed (e.g., for one or more zones associated with the upper) using one or more various known surface analysis techniques, such as X-ray Photoelectron Spectroscopy (XPS) or similar techniques. For example, the surface chemistry of the second zone of the upper (that does not overlap with the sole and is not bonded to the sole) can be analyzed using one or more surface analysis techniques to assess whether the surface of the second zone is different from the transition zone and/or different from the first zone. In at least some examples, the surface analysis technique can be used to determine whether the second zone includes one or more properties that are less conducive to bonding with the sole structure (as compared to the properties of the first zone and/or the transition zone). In at least some examples, the surface analysis technique can be used to determine whether the second zone includes, as compared to the first zone and/or the second zone, higher amounts of a polymeric material (e.g., PU, such as in an ink or other surface layer) that is different from the thermoplastic composition (e.g., thermoplastic polyolefin resin composition) of the sole structure. In at least some examples, the surface analysis technique can be used to determine whether the second zone is, as compared to the first zone and/or the second zone, more oxidized.

At least some examples of this disclosure relate to a strength of a bond between an upper and a sole structure. The strength of the bond can be assed in various manners that measure the ability of the bond to resist delamination when subjected to forces. In some examples, these tests can be referred to as a “peel strength test.” In at least some instances, peel strength can be measured based on SATRA TM411.

“A,” “an,” “the,” “at least one,” and “one or more” might be used interchangeably to indicate that at least one of the items is present. When such terminology is used, a plurality of such items might be present unless the context clearly indicates otherwise. All numerical values of parameters (e.g., of quantities or conditions) in this specification, unless otherwise indicated expressly or clearly in view of the context, including the appended claims, are to be understood as being modified in all instances by the term “about” whether or not “about” actually appears before the numerical value. “About” indicates that the stated numerical value allows some slight imprecision (with some approach to exactness in the value; approximately or reasonably close to the value; nearly). If the imprecision provided by “about” is not otherwise understood in the art with this ordinary meaning, then “about” as used herein indicates at least variations that may arise from ordinary methods of measuring and using such parameters. The term “about” can include +/−10% of a given element, if that numerical definition is necessary to understand the scope of a claimed element. In addition, a disclosure of a range is to be understood as specifically disclosing all values and further divided ranges within the range.

The terms “comprising,” “including,” and “having” are inclusive and therefore specify the presence of stated features, steps, operations, elements, or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, or components. Orders of steps, processes, and operations may be altered when possible, and additional or alternative steps may be employed. As used in this specification, the term “or” includes any one and all combinations of the associated listed items. The term “any of” is understood to include any possible combination of referenced items, including “any one of” the referenced items. The term “any of” is understood to include any possible combination of referenced claims of the appended claims, including “any one of” the referenced claims.

For consistency and convenience, directional adjectives might be employed throughout this detailed description corresponding to the illustrated examples. Ordinary skilled artisans will recognize that terms such as “above,” “below,” “upward,” “downward,” “top,” “bottom,” etc., may be used descriptively relative to the figures, without representing limitations on the scope of the invention, as defined by the claims.

The term “longitudinal,” as possibly used throughout this detailed description and in the claims, refers to a direction extending a length of a component. For example, a longitudinal direction of a shoe extends between a forefoot region and a heel region of the shoe. The term “forward” or “anterior” is used to refer to the general direction from a heel region toward a forefoot region, and the term “rearward” or “posterior” is used to refer to the opposite direction, i.e., the direction from the forefoot region toward the heel region. In some cases, a component may be identified with a longitudinal axis, as well as a forward and rearward longitudinal direction along that axis. The longitudinal direction or axis may also be referred to as an anterior-posterior direction or axis.

The term “transverse,” as possibly used throughout this detailed description and in the claims, refers to a direction extending a width of a component. For example, a transverse direction of a shoe extends between a lateral side and a medial side of the shoe. The transverse direction or axis may also be referred to as a lateral direction or axis or a medio-lateral direction or axis.

The term “vertical,” as possibly used throughout this detailed description and in the claims, refers to a direction generally perpendicular to both the lateral and longitudinal directions. For example, in cases where a sole is positioned flat on a ground surface, the vertical direction may extend from the ground surface upward. It will be understood that each of these directional adjectives may be applied to individual components of a sole. The term “upward” or “upwards” refers to the vertical direction pointing towards a top of the component, which may include an instep, a fastening region, and/or a throat of an upper. The term “downward” or “downwards” refers to the vertical direction pointing opposite the upwards direction, toward the bottom of a component, and may generally point towards the bottom of a sole structure of an article of footwear.

The “interior” of an article of footwear, such as a shoe, refers to portions at the space that is occupied by a wearer's foot when the shoe is worn. The interior can also be referred to as the foot-receiving cavity. The “inner side” of a component refers to the side or surface of the component that is (or will be) oriented toward the interior of the component or article of footwear in an assembled article of footwear. The “inner side” can also be referred to as the “inward-facing side” or “inward-facing surface.” The “outer side” or “exterior” of a component refers to the side or surface of the component that is (or will be) oriented away from the interior of the shoe in an assembled shoe. The “outer side” can also be referred to as the “outer-facing side” or “outer-facing surface, as well as the “exterior-facing side” or “exterior-facing surface.” In some cases, other components may be between the inner side of a component and the interior in the assembled article of footwear. Similarly, other components may be between an outer side of a component and the space external to the assembled article of footwear. Further, the terms “inward” and “inwardly” shall refer to the direction toward the interior of the component or article of footwear, such as a shoe, and the terms “outward” and “outwardly” shall refer to the direction toward the exterior of the component or article of footwear, such as a shoe. In addition, the term “proximal” refers to a direction that is nearer a center of a footwear component, or is closer toward a foot when the foot is inserted in the article of footwear as it is worn by a user. Likewise, the term “distal” refers to a relative position that is further away from a center of the footwear component or is further from a foot when the foot is inserted in the article of footwear as it is worn by a user. Thus, the terms proximal and distal may be understood to provide generally opposing terms to describe relative spatial positions.

Various examples are described below with reference to the drawings, and the structure, relationship, and/or functioning of examples can, in some instances, be better understood by reference to this detailed description. However, examples associated with the subject matter of this application are not limited to those illustrated in the drawings or explicitly described below. The drawings might not necessarily be to scale. In some instances, for clarity, brevity, and/or simplicity details might have been omitted, which does not preclude the inclusion of those details in association with examples of this disclosure.

Reference is now made toto describe elements of a footwear article.depicts a lateral side of the footwear article,depicts a top of the footwear article, anddepicts a partially deconstructed view. In an example, the footwear article can include a soccer/futbol boot. In other examples, the footwear article can include a variety of other types of footwear articles, such as other cleated or non-cleated footwear articles (e.g., for American football, golf, basketball, sportswear/leisure, tennis shoes, hiking boots/shoes, etc.). When describing the various figures mentioned in this disclosure, like reference numbers refer to like components throughout the views (although the components might not be the exact same).

The footwear articleincludes at least two primary elements including a sole structureand an upper. When the footwear articleis worn (as intended on a foot), the sole structureis typically positioned near the foot plantar surface (i.e., the bottom of the foot). The sole structuremay protect the bottom of the foot, and in addition, may attenuate ground-reaction forces, absorb energy, provide traction, and control foot motion, such as pronation and supination. The upperis coupled to the sole structure, and together with the sole structure, forms a foot-receiving cavity(). That is, while the sole structuretypically encloses the bottom of the foot, the upperextends over, and at least partially covers, a dorsal portion of the foot (i.e., the top of the foot or the instep) and secures the footwear articleto the foot. The upperincludes a foot-insertion opening, through which a foot is inserted when the footwear articleis put on as the foot is arranged into the foot-receiving cavity.

As indicated inand, the footwear articlemay include a forefoot region, a midfoot region, a heel region, and an ankle region. The forefoot region, the midfoot region, and the heel regionextend through the sole structureand the upper. The ankle regionis located in a portion of the upper. The forefoot regiongenerally includes portions of the footwear articlecorresponding with the toes and the joints connecting the metatarsals with the phalanges. The midfoot regiongenerally includes portions of the footwear articlecorresponding with the arch area and instep of the foot. The heel regioncorresponds with rear portions of the foot, including the calcaneus bone. The ankle regioncorresponds with the ankle. The forefoot region, the midfoot region, the heel region, and the ankle regionare not intended to demarcate precise areas of the footwear article, and are instead intended to represent general areas of the footwear articleto aid in the understanding of various aspects of this specification. In addition, portions of a footwear article may be described in relative terms using these general zones. For example, a first structure may be described as being more heelward than a second structure, in which case the second structure would be more toeward and closer to the forefoot.

The footwear articlealso has a medial side(identified inand obscured from view in) and a lateral side(identified inand viewable in). The medial sideand the lateral sideextend through each of the forefoot region, the midfoot region, the heel region, and the ankle region, and correspond with opposite sides of the footwear article, each falling on an opposite side of a longitudinal midline reference planeof the footwear article, as is understood by those skilled in the art. For example, the longitudinal midline reference planemay pass through the foremost point of the sole structure and the rearmost point of the sole structure. The medial sideis thus considered opposite to the lateral side. Typically, the lateral side corresponds with an outside area of the foot (i.e., the surface that faces away from the other foot), and the medial side corresponds with an inside area of the foot (i.e., the surface that faces toward the other foot). In another aspect, the footwear article includes an anterior portion (e.g., more forward) and a posterior portion (e.g., more rearward), falling on an opposite side of a latitudinal midline reference planeof the footwear article. The latitudinal midline reference planeextends perpendicular to the longitudinal midline reference planeand to the ground-surface plane and is spaced evenly between the foremost point of the footwear articleand the rearmost point of the footwear article. In addition, these terms may also be used to describe relative positions of different structures. For example, a first structure that is closer to the inside portion of the footwear article might be described as medial to a second structure, which is closer to the outside area and is more lateral. In addition, a first structure that is closer to the forward end of the footwear article might be described as anterior to a second structure, which is closer to the rearward end that is more posterior.

In describing a footwear article, the relative terms “inferior” and “superior” may also be used. For example, the superior portion generally corresponds with a top portion that is oriented closer towards a person's head when the person's feet are positioned flat on a horizontal ground surface and the person is standing upright, whereas the inferior portion generally corresponds with a bottom portion oriented farther from a person's head and closer to the ground surface.

The sole structureof the footwear articlecan comprise a sole component such as one or more plates, midsoles, outsoles, insoles, and the like. In addition, as depicted in the reference view A-A in, at least a portionof the uppercan be affixed to at least a portionof the sole structure. In some examples, at least a portion of the surface of the upperthat is affixed to the sole structurecan comprise a synthetic leather material as described herein, optionally where the affixed surface of the upperis at least partially defined by a polyolefin resin composition as described herein. In some examples, both the affixed surface of the upper, and the affixed surface of the sole structure, can comprise a polyolefin resin composition. The strength of bonds between two surfaces both formed of polyolefin compositions typically are stronger than the strength of bonds between a first surface formed of a polyolefin composition and a non-polyolefin polymeric composition, as the surface energy of polyolefins are typically different from other types of polymeric materials commonly used in footwear manufacturing. As the bond strength of a thermal bond formed between two polyolefin resin compositions is typically greater than an adhesive bond (e.g., a bond formed using a hot-melt adhesive or a cement), when both the surface of the upper and the surface of the sole structure are defined by a polyolefin resin composition, it is advantageous to affix the surfaces together using a thermal bond in which a polyolefin resin composition of the upper and/or of the sole structure is softened or melted and then re-solidified to form the bond.

As used in this disclosure, a “thermal bond” can include a bond between two components that is formed when at least one of the two components is heated to at least a softening point and is brought into contact with the other of the two components, such that upon cooling, the two components are bonded. In some examples, the two components are bonded by a chemical bond, by a mechanical bond, or by a combination of chemical bonds and mechanical bonds. For example, in some cases, a thermal bond can include chemical bonding based on van der Waals forces, dipole interactions, and/or dispersion forces, although covalent bonding of the components might not necessarily be modified or changed (e.g., neither created or destroyed). In at least some examples, a thermal bond can include a mechanical bond, such as where the softened material of the heated component flows around a portion of the other component and, upon cooling, is solidified to at least partially encapsulate the portion. In at least some examples, at least a small amount of material from a first component (e.g., sole structure) might mix with at least a small amount of material from the second component (e.g., the upper, including the portion of the upper that overlaps with the sole structure). An extent of mixing can depend on various factors, such as the extent to which one or both components are heated and/or the amount of time during which heat is applied.

In some examples, the materials of the upper and the sole can both be softened, at least partially mixed together, and then solidified to form the bond. The polyolefin resin composition of the synthetic leather material can be the same as the polyolefin resin composition of the sole structure. The polymeric component of the two polyolefin resin compositions (i.e., the portion of the composition consisting of all the polymers present in the polyolefin resin composition) can include the same types of polymers in the same concentrations, or can include the same types of polymers in different concentrations, or can include different types of polymers. The polyolefin component of the two polyolefin resin compositions (i.e., the portion of the composition consisting of all the polyolefins present in the polyolefin resin composition) can include the same types of polyolefins in the same concentrations, or can include the same types of polyolefins in different concentrations, or can include different types of polyolefins.

In some examples, the sole structurecan be constructed of various other materials and may include various elements (e.g., in addition to the polyolefin resin composition). For example, the sole structuremay include a compressible polymer foam element (e.g., a polyurethane or ethylvinylacetate (EVA) foam) that attenuates ground reaction forces (i.e., provides cushioning) when compressed between the foot and the ground during walking, running, or other ambulatory activities. In further aspects, the sole may incorporate fluid-filled chambers, plates, moderators, or other elements that further attenuate forces, enhance stability, or influence motions of the foot. The sole may be a single, one-piece sole, or could be multiple components integrated as a unit. In some aspects, the sole can include a midsole integrated with an outsole as a unisole. The outsole may be one-piece, or may be several outsole components, and may be formed from a wear-resistant rubber material that may be textured to impart traction and/or may include traction elements such as tread or cleats secured to a midsole. An outsole may extend either the entire length and width of the sole or only partially across the length and/or width.

As indicated, the uppertypically includes a portion that overlaps with, and is connected to, the sole structure. In examples, a bitelineis the junction of the terminal edgeof the sole structurewith the upper. In addition, the footwear articlecan include a strobel(or a lasting board or other lasting panel). The strobelcan function to provide structural integrity across the bottom of the upper, such as when the upperis lasted and is being bonded to the sole structure. In some examples, the strobelcan also contribute to other properties in the footwear article, such as cushioning, motion control (e.g., of the wearer's foot relative to the footwear article), stiffness, etc. The strobel can, in some examples, be covered by an insole or other layer of material.

Examples of the present disclosure are related to the footwear articleassociated with improved bonding (e.g., reduced likelihood of delamination) between the footwear upperand the sole structure. In examples, the footwear upperincludes an outer-facing surface(first zone),(transition zone), and(second zone) that faces away from the foot-receiving cavity. In addition, the outer-facing surface-can include the first zonethat overlaps with, and is bonded to, the sole structure(e.g., a plate or midsole or outsole or other sole component), and in the cross-sectional view in, an extent (e.g., length) of the first zoneis represented by a reference arrow. In examples, the outer-facing surface-can include the second zonethat does not overlap with the sole structure, and in the deconstructed view in, at least part of an extent (e.g., length) of the second zoneis represented by a reference arrow. Examples of the present disclosure are directed to various features of the first zonethat improve bonding to the sole structure, such as bonding via thermal bonding, adhesive bonding, mechanical bonding, chemical bonding, and the like.

In examples, the footwear uppercan include a material (e.g., synthetic leather material) having properties (e.g., chemical composition) that are configured to bond with the sole structure. For example, the sole structurecan include a first thermoplastic composition and the footwear upper(e.g., a textile of the footwear upperand/or a coating or other material coupled to a surface of a textile) can include a second thermoplastic composition, which is configured to bond well with the first thermoplastic composition (e.g., via a thermal bond). Examples of the present disclosure can include the first zoneof the outer-facing surface (e.g., that overlaps with, and is bonded to, the sole structure) having different properties as compared to the second zoneof the outer-facing surface (e.g., that does not overlap with the sole structure). For example, the first zonecan include, on the outermost surface of the outer-facing surface, a first property (e.g.,with the outermost surface represented by the layer), and the first property is different from a second property, which is on the outermost surface of the outer-facing surface in the second zone(e.g.,with the outermost surface represented by the layer, which could be a decorative layer or another layer). In, the second property of the second zoneis indicated by the stippled portionsand, which are absent from the first zone

The first property and the second property can include, among other things, a chemical composition (e.g., a surface chemistry or surface chemical composition), a surface texture, or a combination thereof, or any other surface property that might differ. In some examples, each of the first property and second property is a respective chemical composition, and the first property includes a thermoplastic polyolefin resin composition, which is different from the second property. For instance, the surface in the second zonemight not include any amount of the thermoplastic polyolefin resin composition, or might include less than some threshold amount (e.g., less than 5% percentage composition, such as by weight). In some examples, the second property can include a cleaning-solution composition, a more oxidized surface (as compared to the first zone), a primer composition, an ink composition (e.g., a polyurethane or other chemical composition that is different from the thermoplastic polyolefin resin composition), a surface texture, or any and all combinations thereof. The second zonecan have different properties in different regions of the upper. For example, the second zonecan have in some areas (e.g.,depicted with a first stipple pattern) an ink composition, and the second zonecan have in some other areas (e.g.,depicted with a second stipple pattern) different properties imparted by a different ink composition, corona treatment, cleaning solution, etc.). In examples, the first property can contribute to improved bond strength between the footwear upper and the sole structure.

Referring to, an example is illustrated related to the second zonehaving a surface texture (e.g., grooves or other debossed or impressed shapes or patterns) with one or more relief depthsand. A relief depth is a distance between an outermost surface of the second zoneand the base or bottom surface the relief portion. In at least some examples, the relief depth can be about zero. In at least some examples, the second property that is associated with the second zonecan include a larger relief depth (e.g.,). In at least some examples, the relief depth can taper from a larger relief depth to a smaller relief depth as the outermost surface extends from a first position that is further away from the biteline to a second position that is closer to the biteline. In examples, the taper can be to a relief depth of almost zero. In at least some examples, the taper can decrease the likelihood that the surface texture might decrease a peel strength of a bond between the upperand the sole structure. Stated differently, in at least some examples, if portions of the upper that overlap with the sole structure (e.g., for bonding) include a larger relief depth, there can be a higher likelihood that the part of the upper with the relief might contact the sole structure to a lesser extent (e.g., as compared to an upper with a lower relief), and as such, reducing the relief height can increase the likelihood that that part of the upper (with the relief) with have greater contact (e.g., over a greater surface area) and can form a stronger bond.

The first zonecan include a width (e.g., as represented by the arrow) that extends from a terminal edgeof the upper(e.g., the terminal edge that is wrapped beneath the footbed) to a position aligned with the biteline. In at least some examples, the width can vary depending on a position of the first zone. For example, a first width of the first zonealong the midfoot can differ from a second width of the first zone in the forefoot. In some examples, the varied widths associated with the first zonecan contribute to balancing of various overall (and sometimes competing or conflicting) properties. For instance, at some positions, the first zone can include a larger width where increased bond strength is desired between the upper and other underfoot structures (e.g., the sole, lasting board, etc.), whereas in other positions the first zone can include a smaller width where sufficient bond strength can be achieved with less bonding surface area and the smaller width can contribute to less overall materials and a lower overall weight (of the footwear article).

In at least some examples, the outer-facing surface can include a transition zonethat is positioned spatially between the first zoneand the second zone. In examples, the outermost surface of the transition zoneis not bonded to the sole structure. For example, the transition zonecan extend from a position that is aligned with the bitelineand to the second zone. In addition, the transition zone can include properties (e.g., a chemical composition, a surface texture, or a combination thereof, or any other surface property) that are similar to the first zoneand that are different from the second zone. In examples, the transition zonecan include a buffer zone that safeguards against properties of the second zonebeing associated with a surface bonded to the sole structure, which could otherwise reduce the likelihood of bonding failure and delamination. In at least some instances, the transition zonecan extend around the entire periphery of the footwear article (e.g., along the entire biteline). In some instances, the transition zonecan extend around a portion of the periphery of the footwear article (e.g., along a portion of the biteline).

In some examples, a width of the transition zone (as represented by the reference arrow) can vary depending on a position around the periphery. For example, a cross-reference B-B is identified in, and the dimensionof the transition zoneis labeled accordingly. In some examples, the width dimensionin the forefoot or toebox can be smaller than the corresponding width dimensionof the transition zonein along other regions of the footwear article. Among other things, providing smaller transition zone can reduce a possible disruption in the surface coverage associated with the second zone(e.g., ink or other print components; protective layer; abrasion resistant layer; etc.) in desired areas (e.g., areas that might be more visible), while still ensuring some buffer between the second zoneand the biteline.

In at least some examples, the strobel(e.g., see also) is affixed to a margin of the upperthat is at least partially wrapped underneath the footbed. The strobel(or any portion of the strobel) can be affixed to the upperin various manners, such as by stitching, adhering, chemical bonding, mechanical bonding, thermal bonding, and any combination thereof. In some examples an inner-facing surface(e.g.,and) that faces towards the foot-receiving cavityis adhered to the strobel. For example, a hotmelt glue (e.g.,in) can bond the inner-facing surfaceto the strobel. In some examples, a portion or segment of the upper can be adhesively bonded to the strobel, while another, different portion or segment of the upper can be stitched.

Referring toa partially deconstructed view of a footwear articleis depicted, and unless otherwise expressly indicated, the footwear articlecan include the same features as depicted and described with respect toand. For example, the footwear articleincludes the upperthat bonds to the sole structure, and a portion or zoneof the upper overlaps with and is bonded directly to the sole structure. In addition, the footwear articlecan include the inner-facing surfacethat is affixed to the strobel. Furthermore, the uppercan include the second zone, which includes different properties as compared with the zone, and for illustration purposes, a theoretical bitelineis identified.

In examples of this disclosure, the portion of the upperthat extends below the bitelinecan be referred to as a bonding skirt (e.g., bonding selvage) and is identified by reference numeralin(see also Reference View A-A in). In at least some examples, the bonding skirtincludes the zoneof the outer-facing surface. In some examples, the bonding skirtcan include the inner-facing surface. In some examples of the present disclosure, the bonding skirtcan include a size dimension (e.g., width) as measured from the edgeto the biteline, and in Reference View A-A in, the width dimension of the bonding skirtis identified by reference numeral.

In examples, the widthof the bonding skirtas measured from the edgeto the bitelinecan be consistent at two or more positions around the periphery of the footwear article. For example, the dimension of the bonding skirtcan be the same at two or more of the heel region, the midfoot region, the toebox region, the medial side, the lateral side, and any combinations thereof.

In some examples of the present disclosure, a dimension of the bonding skirt(e.g., a width dimension) as measured from the edgeto the bitelinecan vary as between two or more positions around the periphery of the footwear article. For example, the dimension of the bonding skirtat a position associated with a toebox or forefoot can be greater than the dimension of the bonding skirtat a more posterior portion of the footwear article. As an illustration, a cross-reference B-B is identified in, and the dimensionof the bonding skirtis labeled accordingly. In some examples, the width dimensioncan be larger than the width dimension. Among other things, providing a larger bounding skirtwith more surface area (e.g., on the outer-facing surface and on the inner-facing surface) can provide for stronger bonding to the sole structureand/or to the strobelin areas that can be subject to larger or more frequent forces (e.g., such as resulting from activity of the wearer).

A footwear article that includes the first zone, the transition zone, and the second zonecan be constructed or manufactured in various manners (e.g., illustrated operations in). In some examples, before the upper is bonded to the sole structure, the upper can include a first surface (e.g.,in), which is configured to operate or function as an outer-facing surface when the upper is bonded to the sole structure, and a second surface that is configured to operate as an inner-facing surface (e.g., facing towards the foot-receiving cavity). In at least some examples the first surface, which will eventually function as the outer facing surface, can include one or more properties (e.g., chemical composition, texture, etc.) that are conducive to bonding (e.g., thermal bonding) with the sole structure. For example, the first surface can include a thermoplastic composition (e.g., thermoplastic polyolefin resin composition) that is configured to form a strong bond with a thermoplastic composition (e.g., thermoplastic polyolefin resin composition) of the sole structure.

In some examples, a maskis applied to the first surface (e.g., to a masked portion of the first surface) and along a peripheral margin of the upper. The mask (e.g., and the masked portion of the first surface) can extend from the terminal peripheral edge of the upper (e.g., from the edgethat will be wrapped underneath the footbed and in some instances attached to a lasting board or strobel) and inward to a position that extends beyond the portion of the first surface that will eventually align with the biteline when the upper is affixed to the sole. In addition, the mask can terminate at the position beyond the eventual biteline and leave a central portion of the first surface exposed. That is, the maskcan extend from the terminal peripheral edge of the upper and inward beyond the eventual biteline, and this portion inwardly beyond the eventual biteline (and to the central exposed portion) can operate as the transition or buffer zone. With the mask applied, the first surface can include a masked peripheral margin and an exposed central portion. In some examples, at least a portion of the upper that is covered by the mask will operate as the first zoneassociated with the bonding skirt (e.g.,). In some examples, at least a portion of the upper that is covered by the mask will include the transition zone

In some examples, with the mask applied to the first surface and along the peripheral margin, one or more operations are performed on the exposed central portion of the first surface, and the one or more operations can modify the surface properties of the exposed central portion. In examples, the mask reduces the likelihood of the operations modifying the surface properties of the masked peripheral margin (e.g., the thermoplastic composition of the masked peripheral margin can still include a state that is conducive to bond with the sole structure, despite properties of the exposed central portion being modified). In at least one example, the operation can include cleaning the first surface by applying a cleaning agent, and the application of the cleaning agent can modify the surface properties of the exposed central portion while the mask reduces the likelihood of changes to the masked peripheral margin. In at least one example, the operation can include subjecting the first surface to a corona treatment, and the corona treatment can modify the surface properties of the exposed central portion (e.g., by oxidizing the surface) while the mask reduces the likelihood of changes to the masked peripheral margin. In some examples, the operation can include applying a primer to the first surface, and the primer can modify the surface properties of the exposed central portion while the mask reduces the likelihood of changes to the masked peripheral margin. In some examples, the operation can include applying an ink to the first surface (e.g., by a screen printing or other ink-application process), and the ink (e.g., including at least some polymers other than a polyolefin) can modify the surface properties of the exposed central portion while the mask reduces the likelihood of changes to the masked peripheral margin. In some examples, the operation can include applying a surface texture the first surface (e.g., by depositing a material in a pattern having a relief and/or by impressing a surface texture into the surface), and the surface texture (e.g., including a relief having a depth) can modify the surface properties of the exposed central portion while the mask reduces the likelihood of changes to the masked peripheral margin.

In at least some examples, after the one or more operations that modify the surface properties of the exposed central portion, the mask can be removed to expose the peripheral margin of the first surface, which still includes the one or more properties (e.g., chemical composition, texture, etc.) that are conducive to bonding (e.g., thermal bonding) with the sole structure. As indicated above, the now uncovered peripheral margin can include the portions that will include the first zoneand the transition zone

The upper can be lasted using one or more various lasting techniques. In some examples, a strobel or lasting board is coupled (e.g., via stitching, adhesive, etc.) to the second surface of the upper (e.g., the surface on the opposite side of the upper as the first surface, and otherwise referred to herein as the inner-facing surface). For example, the peripheral margin of the upper (e.g., the bonding skirt) can be wrapped underneath the last (e.g., by stretching or pulling the peripheral margin) and attached to the strobel or lasting board. In some examples, the strobel is positioned on the underneath side of the last, and the bonding skirtis pulled down underneath the last and affixed to the underneath side of the strobel. In some examples, a portion of the upper (a portion of the bonding skirt) can be pre-attached to the strobel prior to positioning on the last. For example, the pre-attachment can be via stitching, adhesive, or any other strobel attachment technique. In some examples, the pre-attachment can occur in the heel region.

In some examples, various portions of the bonding skirtare stretched to varying degrees beneath the last when attach the bonding skirtto the strobel (e.g., attaching the inner-facing surface of the bonding skirtto the underneath side of the strobel). In some examples, added tension is desired to ensure as much of the outer-facing surface as possible is available for bonding to the sole structure. In some examples, added tension is desired to minimize a size of the transition zone. In some examples, less tension is applied to ensure sufficient buffer between the second zoneand the actual biteline (e.g., once the sole structure is attached). In some examples, the different tension applied at different regions of the bonding skirtcan contribute to the theoretical biteline and the transition zonebeing pulled either further underneath the last or positioned higher up on the last. As such, once the sole structure is bonded to the upper (e.g., direct injection molded onto the upper with the upper on the last), the width (e.g.,) can vary at different positions around the periphery.

In examples, with the upper arranged on the last one or more additional operations can be executed to attach the upper to the strobel and/or to prepare the upper for bonding to the sole structure. For example, in some instances in which the upper (e.g., the inner facing surface of the upper) is adhesively bonded to the strobel or lasting board (e.g., via a hotmeltalong a bonding interface), the upper can be sanded or buffed (e.g., near 129 in) to reduce the likelihood excess adhesive on the first surface of the upper, which can increase the likelihood of the peripheral margin of the first surface retaining the one or more properties (e.g., chemical composition, texture, etc.) that are conducive to bonding (e.g., thermal bonding) with the sole structure. Additional bonding and sanding/buffing can be performed, when needed, to sufficiently bond any portions of edges to the strobel or lasting board.

More specifically, in some examples, the strobel and the inner-facing side of the upper (e.g., the inner-facing side of the bonding skirt) can include a textile or a composite textile, including a knit textile, a woven textile, a nonwoven textile, a spacer textile, a foam layer, and any combinations thereof. In at least one example, at least the underneath side of the strobel(e.g., the side that faces away from the foot-receiving cavity) and the inner-facing sideof the bonding skirtcan include a respective nonwoven textile. In addition, in some examples, the underneath side of the strobelcan be adhesively bonded (e.g., via) to the inner-facing surfaceof the upper (e.g., along the bonding skirt) via a hotmelt film (e.g., a thermoplastic polyurethane (TPU) hotmelt film). As such, the bonding interface can include fibers of the strobel nonwoven textile and fibers of the inner-facing surface nonwoven textile adhesively bonded via the hotmelt film (e.g., the fibers are mechanically entrapped and/or encapsulated in the hotmelt film). In some examples, hotmelt film can extend to the terminal edge of the upper (e.g., the terminal edge along the portion that is pulled underneath the last and affixed to the strobel) and continuously along the edge (e.g., near 129). In this respect, the adhesive bond between the strobel and the upper can include a sealed edge (e.g., along 129) that operates as a barrier to other materials flowing or wedging into any gaps between the strobel and the bonding skirt and reducing the likelihood of delamination. For example, in a footwear article with this type of sealed edge or sealed bonding interface between the strobel and the inner-facing surface of the upper, the bond can be substantially free (e.g., equal to or less than 10%) of the sole-structure composition (e.g., a thermoplastic composition that is direct injected onto the strobel and upper under pressure and that, absent the sealed bonding interface, could enter gaps or spaces and cause delamination between the upper and strobel).

In addition, as indicated above, any excess hotmelt film (e.g., TPU hotmelt film) can be removed from the underneath side of the stobel that is not covered by the bonding skirt and from along the sealed edge (e.g., if any excess hotmelt has seeped out beyond the terminal edge). Among other things, removal of excess hotmelt (e.g., near 129) can reduce the likelihood that the thermoplastic composition of the hotmelt will soften and/or remelt and mix with the thermoplastic composition of the sole structure when the sole structure is bonded to the lasted upper (e.g., via direct injection molding).

In some examples, after the upper has been bonded (e.g., viain) to the strobel or lasting board, the upper can be bonded to the sole structure. For example, the sole structure can be bonded to the peripheral margin of the first surface (e.g., facing away from the last), which still includes the one or more properties (e.g., chemical composition, texture, etc.) that are conducive to bonding (e.g., thermal bonding) with the sole structure. In some examples, the sole structure can be directly injected (e.g., through an injection molding operation) onto the lasted upper, such that the sole structure bonds to the peripheral margin of the first surface. For example, a sole-structure mold can be positioned relative to the lasted upper and an edge of the mold can be positioned within the peripheral margin of the first surface (which includes the one or more properties), and the edge of the mold can be spaced apart from the portion having the modified properties (e.g., as a result of the cleaning, corona treatment, primer, ink, etc.). In examples, a thermoplastic composition of the sole structure can be deposited into the mold and can thermally bond to the peripheral margin of the first surface, thereby creating the first zone (e.g., with the first property and bonded to the sole structure), the transition zone (e.g., with the first property and not bonded to the sole structure), and the second zone (e.g., with the second property different from the first property and not bonded to the sole structure).