Bladder for an Article of Footwear

This application claims priority under 35 U.S.C. § 119 (e) to U.S. Provisional Application No. 63/569,787, filed on Mar. 26, 2024. The disclosure of this prior application is considered part of the disclosure of this application and is hereby incorporated by reference in its entirety.

The present disclosure relates generally to a bladder for an article of footwear or apparel and a method for forming a bladder for an article of footwear or apparel.

This section provides background information related to the present disclosure and is not necessarily prior art.

Bladders or airbags are used in articles of footwear and apparel to provide cushioning and other performance characteristics during use. Such bladders typically include one or more polymeric films forming an outer layer of the bladder and defining an interior chamber that contains a compressible material, such as a fluid, an elastomeric material, and/or a tensile structure. The fluid and/or elastomeric material provide the bladder with the ability to absorb and cushion forces applied thereto while the tensile member helps maintain a desired shape of the bladder in a relaxed state.

In articles of footwear, bladders are traditionally concealed within a sole structure of the article of footwear to provide cushioning and responsiveness to a wearer during use. Such bladders may be contained within a midsole of the article of footwear and, as a result, are hidden from view. Alternatively, a midsole may include one or more openings where the bladder is visible at a sidewall of the sole structure. Such openings may be so large, in fact, that the bladder forms a majority of a thickness of the sole structure. In such a configuration, a sidewall of the bladder may extend between and join an upper of the article of footwear and a ground-contacting surface of the article of footwear.

Regardless of the particular structure of the bladder and its relationship to other components of the sole structure, the shape, color, and overall appearance of the bladder are typically designed to complement the surrounding structure of the article of footwear and/or the article of apparel to provide the article of footwear and/or the article of apparel with a desired appearance.

Corresponding reference numerals indicate corresponding parts throughout the drawings.

Example configurations will now be described more fully with reference to the accompanying drawings. Example configurations are provided so that this disclosure will be thorough, and will fully convey the scope of the disclosure to those of ordinary skill in the art. Specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of configurations of the present disclosure. It will be apparent to those of ordinary skill in the art that specific details need not be employed, that example configurations may be embodied in many different forms, and that the specific details and the example configurations should not be construed to limit the scope of the disclosure.

The terminology used herein is for the purpose of describing particular exemplary configurations only and is not intended to be limiting. As used herein, the singular articles “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. Additional or alternative steps may be employed.

When an element or layer is referred to as being “on,” “engaged to,” “connected to,” “attached to,” or “coupled to” another element or layer, it may be directly on, engaged, connected, attached, or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” “directly attached to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (“between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.

The terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections. These elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example configurations.

In one configuration, a bladder for an article of footwear includes a first barrier layer, a second barrier layer coupled to the first barrier layer at a peripheral seam, a chamber defined between the first barrier layer and the second barrier layer and defining an interior void, and a knit infill material disposed within the interior void of the chamber between the first barrier layer and the second barrier layer and including a first material and a second material, the first material comprising a fusible yarn.

The bladder may include one or more of the following optional features. For example, the second material may comprise polyester yarn. Additionally or alternatively, the first material may comprise nylon and/or a polyamide material.

In one configuration, the knit infill material may include a series of alternating peaks and valleys. The knit infill material may be moveable between an expanded state and a compressed state, apexes of adjacent peaks moving toward one another when the knit infill material is moved into the compressed state. In this configuration, the knit infill material may be moved into the compressed state in response to fluid being removed from the interior void. Additionally or alternatively, the knit infill material may be biased into the expanded state.

The knit infill material may be attached to at least one of the first barrier layer and the second barrier layer. An article of footwear may incorporate the bladder.

In another configuration, a method is provided and includes coupling a first barrier layer to a second barrier layer at a peripheral seam to define a chamber between the first barrier layer and the second barrier layer, the chamber including an interior void. The method also includes positioning a knit infill material within the interior void of the chamber between the first barrier layer and the second barrier layer, the knit infill material including a first material comprising a fusible yarn and a second material.

The method may include one or more of the following optional steps. For example, the second material may comprise polyester yarn. Additionally or alternatively, the first material may comprise nylon and/or a polyamide material.

In one configuration, the knit infill material may be provided with a series of alternating peaks and valleys. Positioning a knit infill material within the interior void of the chamber may include positioning a knit infill material that is moveable between an expanded state and a compressed state, apexes of adjacent peaks moving toward one another when the knit infill material is moved into the compressed state. In one configuration, fluid may be removed from the interior void to move the knit infill material into the compressed state. Additionally or alternatively, the knit infill material may be biased into the expanded state.

The first material may flow when forming the series of alternating peaks and valleys. In this configuration, the first material may be cooled after formation of the series of alternating peaks and valleys.

The details of one or more implementations of the disclosure are set forth in the accompanying drawings and the description below. Other aspects, features, and advantages will be apparent from the description, the drawings, and the claims.

With reference to, an example of an article of footwearis illustrated including a bladderconfigured with a knit infill materialdisposed within a throatof the footwear. The principles of the present disclosure may be used for forming bladdersused in other parts of the article of footwear, such as in an upperor a sole structureof the article of footwear. The principles of the present disclosure may also be used for forming bladdersused in other articles including, but not limited to, articles of apparel.

Referring to, an example mold assemblyfor molding the knit infill materialof the bladderis provided. The mold assemblyincludes a first moldand a second mold. The first moldhas one or more first mold projections, and the second moldhas one or more second mold projectionsthat cooperate with the first mold projectionsto define a respective mold patternthat defines a shape and surface profile of the knit infill material. In the illustrated example, the first moldincludes a first patternformed along a mold surfaceand the second moldincludes a second patternformed along a second mold surface. The second patterncooperates with the first patternto form a configuration of the knit infill material, referred to as an infill geometry. For example, the patterns,of the molds,are illustrated as having a wave pattern. As described in more detail below, the knit infill materialis molded with the patterns,to define the infill geometryand, more particularly, to provide the infill geometry with a waveform geometry.

Prior to molding the knit infill material, the first moldand the second moldare preheated to define an even, elevated temperature along each of the first surfaceand the second surface. For example, the mold assemblymay be preheated to approximately 160 degrees Celsius. It is also contemplated that the mold assemblymay be preheated to a temperature greater than or less than 160 degrees Celsius. Once the first and second molds,are preheated, the knit infill materialis positioned between the first moldand the second moldalong one of the first surfaceand the second surfaceand a first pressure is applied.illustrates an example press systemin which the mold assemblyand the knit infill materialmay be positioned.

The press systemmay include an upper platen opposing the first moldand a second platen opposing the second mold. As the platens are moved toward one another, a pressure is applied to the first moldand the second mold, thereby causing the first moldand the second moldto move toward one another. In so doing, the first moldand the second moldcompress the knit infill materialbetween the first moldand the second mold. The press systemmay additionally include a heating element (not shown) associated with one or more of the first platen and the second platen. The heating element may heat the first platen and/or the second platen, thereby heating the first moldand the second mold. The applied heat may be transferred to the knit infill materialduring compression of the knit infill materialbetween the first moldand the second mold.

The applied heat assists in softening the knit infill material, which may mold to the first and second patterns,under the applied first pressure. In some examples, the mold assemblymay apply the first pressure to the knit infill materialvia the press systemat a temperature of approximately 160 degrees Celsius. Specifically, the applied heat is transferred to the knit infill materialvia the molds,, thereby causing the knit infill materialto become softened. At the same time, pressure is applied to the knit infill materialvia the press systemand the first and second molds,to allow the first patternand the second patternto deform and shape the infill materialinto the infill geometry. In some examples, the first pressure may be applied for approximately (60) seconds. In other examples, the first pressure may be applied for greater than approximately sixty (60) seconds or less than approximately sixty (60) seconds. The application of the first pressure in combination with the applied heat defines a first mold impression along the knit infill material.

Referring still to, after the first predetermined period of time, the first pressure is removed and the mold assemblyand knit infill materialmay be cooled. For example,illustrates the mold assemblywith the knit infill materialdisposed therein after formation of the knit infill materialinto the infill geometry(i.e., after deformation of the infill materialinto the geometry shown in). As illustrated in, the knit infill materialis molded to the first and second patterns,of the respective first and second molds,. As previously described, the first and second patterns,of the respective molds,include a series of alternating peaks and valleys that provide the knit infill materialwith a waveform infill geometryhaving a series of alternating peaks and valleys.

Additionally, the molded knit infill materialmay have a second pressure applied thereto immediately following the application of the first pressure with or without first executing a cooling step. For example, the press systemand the first and second molds,may apply a second pressure to the knit infill materialvia the first and second molds,. The application of the second pressure may occur after allowing the molds,and/or the molded knit infill materialto cool or may be applied without allowing the molds,and/or the molded infill materialto cool.

In other examples, the second pressure may be applied during a cooling period. For example, a cooling step may occur simultaneously with the application of the second pressure to define the molded knit infill material. For example, the infill materialhaving the waveform infill geometrymay be removed from the first and second molds,and may be placed in a second set of identical molds,. The second set of identical molds,may be used in conjunction with a press system that is identical to the press systemto provide for application of the second pressure to the second set of identical molds,. The application of the second pressure to the molded knit infill materialmay be identical to the process described above with respect to the application of the first pressure to the knit infill materialbut is performed without heating the platens of the press systemor the molds,. For example, the second pressure may be applied at room temperature and may be applied to the mold assemblyand the molded knit infill materialfor a second period of time. The second period of time may, in some examples, be approximately sixty (60) seconds. In other examples, the first pressure may be applied for greater than approximately sixty (60) seconds or less than approximately sixty (60) seconds.

With further reference to, the bladderincludes a first film or barrier layerand a second film or barrier layerthat cooperate to define an interior void. The first barrier layeris coupled to the second barrier layerto form the interior voidof the bladder. Interior surfaces of the barrier layers,face each other and are joined to each other to form a chambersealed by a peripheral seamthat surrounds the interior voidof the bladder. As described herein, the bladdermay be formed via a thermoforming process. However, it is also contemplated that the bladdermay be formed via a blow molding process, such that the bladdermay be free from the peripheral seam.

As used herein, the term “barrier layer” (e.g., barrier layers,) encompasses both monolayer and multilayer films. In some embodiments, one or both of barrier layers the,are each produced (e.g., thermoformed or blow molded) from a monolayer film (a single layer). In other embodiments, one or both of the barrier layers,are each produced (e.g., thermoformed or blow molded) from a multilayer film (multiple sublayers). In either aspect, each layer or sublayer can have a film thickness ranging from approximately 0.2 micrometers to approximately 1 millimeter. In further embodiments, the film thickness for each layer or sublayer can range from approximately 0.5 micrometers to approximately 500 micrometers. In yet further embodiments, the film thickness for each layer or sublayer can range from approximately 1 micrometer to approximately 100 micrometers.

One or both of the barrier layers,can independently be transparent, translucent, and/or opaque. As used herein, the term “transparent” for a barrier layer means that light passes through the barrier layer in substantially straight lines and a viewer can see through the barrier layer. In comparison, for an opaque barrier layer, light does not pass through the barrier layer and one cannot see clearly through the barrier layer at all. A translucent barrier layer falls between a transparent barrier layer and an opaque barrier layer, in that light passes through a translucent layer but some of the light is scattered so that a viewer cannot see clearly through the layer.

The barrier layers,can each be produced from an elastomeric material that includes one or more thermoplastic polymers and/or one or more cross-linkable polymers. In an aspect, the elastomeric material can include one or more thermoplastic elastomeric materials, such as one or more thermoplastic polyurethane (TPU) copolymers, one or more ethylene-vinyl alcohol (EVOH) copolymers, and the like.

As used herein, “polyurethane” refers to a copolymer (including oligomers) that contains a urethane group (—N(C—O)O—). These polyurethanes can contain additional groups such as ester, ether, urea, allophanate, biuret, carbodiimide, oxazolidinyl, isocynaurate, uretdione, carbonate, and the like, in addition to urethane groups. In an aspect, one or more of the polyurethanes can be produced by polymerizing one or more isocyanates with one or more polyols to produce copolymer chains having (—N(C═O)O—) linkages.

Examples of suitable isocyanates for producing the polyurethane copolymer chains include diisocyanates, such as aromatic diisocyanates, aliphatic diisocyanates, and combinations thereof. Examples of suitable aromatic diisocyanates include toluene diisocyanate (TDI), TDI adducts with trimethyloylpropane (TMP), methylene diphenyl diisocyanate (MDI), xylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), hydrogenated xylene diisocyanate (HXDI), naphthalene 1,5-diisocyanate (NDI), 1,5-tetrahydronaphthalene diisocyanate, para-phenylene diisocyanate (PPDI), 3,3′-dimethyldiphenyl-4,4′-diisocyanate (DDDI), 4,4′-dibenzyl diisocyanate (DBDI), 4-chloro-1,3-phenylene diisocyanate, and combinations thereof. In some embodiments, the copolymer chains are substantially free of aromatic groups.

In particular aspects, the polyurethane polymer chains are produced from diisocynates including HMDI, TDI, MDI, H12 aliphatics, and combinations thereof. In an aspect, the thermoplastic TPU can include polyester-based TPU, polyether-based TPU, polycaprolactone-based TPU, polycarbonate-based TPU, polysiloxane-based TPU, or combinations thereof.

In another aspect, the polymeric layer can be formed of one or more of the following: EVOH copolymers, poly(vinyl chloride), polyvinylidene polymers and copolymers (e.g., polyvinylidene chloride), polyamides (e.g., amorphous polyamides), amide-based copolymers, acrylonitrile polymers (e.g., acrylonitrile-methyl acrylate copolymers), polyethylene terephthalate, polyether imides, polyacrylic imides, and other polymeric materials known to have relatively low gas transmission rates. Blends of these materials as well as with the TPU copolymers described herein and optionally including combinations of polyimides and crystalline polymers, are also suitable.

The barrier layers,may include two or more sublayers (multilayer film) such as shown in Mitchell et al., U.S. Pat. No. 5,713,141 and Mitchell et al., U.S. Pat. No. 5,952,065, the disclosures of which are incorporated by reference in their entirety. In embodiments where the barrier layers,include two or more sublayers, examples of suitable multilayer films include microlayer films, such as those disclosed in Bonk et al., U.S. Pat. No. 6,582,786, which is incorporated by reference in its entirety. In further embodiments, barrier layers,may each independently include alternating sublayers of one or more TPU copolymer materials and one or more EVOH copolymer materials, where the total number of sublayers in each of the barrier layers,includes at least four (4) sublayers, at least ten (10) sublayers, at least twenty (20) sublayers, at least forty (40) sublayers, and/or at least sixty (60) sublayers.

The chambercan be produced from the barrier layers,using any suitable technique, such as thermoforming (e.g. vacuum thermoforming), blow molding, extrusion, injection molding, vacuum molding, rotary molding, transfer molding, pressure forming, heat sealing, casting, low-pressure casting, spin casting, reaction injection molding, radio frequency (RF) welding, and the like. In an aspect, the barrier layers,can be produced by co-extrusion followed by vacuum thermoforming to produce the chamber.

In some embodiments, the chamberhas a gas transmission rate for nitrogen gas that is at least approximately ten (10) times lower than a nitrogen gas transmission rate for a butyl rubber layer of substantially the same dimensions. In an aspect, chamberhas a nitrogen gas transmission rate of 15 cubic-centimeter/square-meter·atmosphere·day (cm/m·atm·day) or less for an average film thickness of 500 micrometers (based on thicknesses of the barrier layers,). In further aspects, the transmission rate is 10 cm/m·atm·day or less, 5 cm/m·atm·day or less, or 1 cm/m·atm·day or less.

The barrier layers,are bonded together at the peripheral seam, as mentioned above, and the molded knit infill material(i.e., the knit infill material having the waveform infill geometry) is disposed within the chamber. While the barrier layers,are bonded at the peripheral seam, the knit infill materialis generally unattached or otherwise unbonded with the barrier layers,. For example, the knit infill materialis positioned within the interior voidwhile being free from bonding with the barrier layers,. Thus, the bladderincludes the knit infill materialdisposed within the interior voidof the chamberbetween the first barrier layerand the second barrier layer. It is contemplated that the bond along the peripheral seammaintains the position of the knit infill materialwithin the chamberwhile being free from direct bonding between the barrier layers,and the knit infill material. Additionally or alternatively, in other examples, portions of the knit infill materialmay be selectively attached to the barrier layers,.

For example, as illustrated in, the knit infill materialincludes a perimeter edgethat is free from peaks and valleys and, thus, is substantially flat. The perimeter edgemay be positioned between the barrier layers,along the peripheral seamto anchor the knit infill materialwithin the chamberaround a majority or an entirety of the perimeter edge. In other examples, a portion of the peripheral seamproximate to the interior voidmay remain unbonded during manufacturing, such that the perimeter edgeof the knit infill materialmay be placed between the barrier layers,during assembly while remaining free from direct bonding with the barrier layers,. At this point, the portion of the perimeter edgedisposed between the barrier layers,at the peripheral seammay be joined to the barrier layers,to fix the perimeter edgefor movement with the peripheral seam. In situations where the knit infill materialis not attached to the barrier layers,, the perimeter edgeof the knit infill materialmay abut the bladderproximate to the peripheral seamto aid in fixing a position of the knit infill materialrelative to and within the bladder.

Referring now to, the knit infill materialincludes a first material and a second material. It is contemplated that the first material may be a fusible yarn and the second material may be a polyester yarn. In one example, the knit infill materialmay be approximately fifty (50) percent fusible yarn and approximately fifty (50) percent polyester yarn. In other examples, the knit infill materialmay include greater than approximately fifty (50) percent of one of the first material and/or the second material and a correspondingly adjusted ratio for the other of the first material and/or the second material. In some examples, the first material may be a nylon or polyamide material. The first material is configured to provide additional stiffness to the knit infill materialand, thus, the bladder. For example, the first material may have a larger knit denier as compared to the second material. Further, when heat is applied to the knit infill material, the applied heat may cause the first material to at least partially melt and flow, thereby causing the infill materialto conform to the geometries of the first moldand the second mold. The material of the first material may meld with itself and, further, may fuse the material of the second material into the shape shown in. Accordingly, when the knit infill materialcools, the first material once again hardens and retains the waveform shape imparted to the knit infill materialby the first moldand the second mold.

In some configurations, the first material may have a different color than the second material, such that the contrasting colors of the first and second materials provides the knit infill materialwith a color-changing appearance. For example, the knit infill materialmay be configured to appear to change colors between a relaxed state () and a constricted state () of the bladder. As the bladdertransitions between the relaxed state and the constricted state, the first and second materials cooperate to define a color change appearance of the knit infill material. As the fibers of the first and second materials are drawn together and apart, the fibers change position. In so doing, the fibers provide the infill materialwith a change in appearance (i.e., color) when the infill materialis moved with the bladderbetween the relaxed state and the constricted state.

The first and second materials may be interwoven via a mesh needle, which defines a plurality of openingsalong the knit infill material. The openingsare configured to provide the knit infill materialwith a degree of flexibility, while the infill geometrymaximizes the structural density. The plurality of openingsmay have a generally circular shape prior to molding of the knit infill materialand, after the molding process, have a generally oblong or elongated shape. For example,illustrates an enlarged view of a portion of the molded knit infill materialwith individual threadsinterspaced with the plurality of openings. It is contemplated that the threadsare formed from the interwoven first material and second material, which collectively define the openings. As generally mentioned above, the knit infill materialis molded into a waveform geometry, such that a plurality of peaksand valleysare defined along the knit infill material. The mold assembly() is configured to define a large number of peaksand valleysalong the knit infill material. This structure provides the molded knit infill materialwith the ability to flex and bend while still retaining the waveform infill geometryprovided by the peaksand valleys. In short, the peaksand valleysallow the knit infill materialto easily bend about a longitudinal axis of each peakand valley, resist such bending in a direction substantially perpendicular to the longitudinal axis of each peakand valley, and retain the overall waveform shape of the molded infill material.

The peaksmay be spaced apart in a row by approximately 2.6 millimeters to define the valleys. In other examples, the peaksmay be spaced apart by more than approximately 2.6 millimeters or less than approximately 2.6 millimeters. Each of the peaksincludes an apexat which the knit infill materialis configured to flex or hinge between a relaxed state and a compressed state. For example, the peaksare designed to hinge the knit materialabout the respective apexto draw sidewallsof the peakstogether in the compressed state. The constriction of the sidewallstoward one another ultimately constricts the knit infill materialand, thus, the bladder. The resilient nature of the molded infill materialcauses the peaksto be biased into the relaxed or expanded state. Accordingly, when a force exerted on the infill materialthat causes the infill materialto be in the compressed state is released, the resilient nature of the infill material, along with the shape of each peak, causes the infill materialto automatically move into the relaxed or expanded state such that adjacent peaksmove away from one another.

As described herein, the bladdermay be integrated as a portion of an article of footwear(), such that the constriction of the peaksof the knit infill materialconstricts the portion of the footwearin which the knit infill materialand bladderare incorporated. The peaksof the knit infill materialmay, in some examples, have a height Hof approximately 10.5 millimeters. In other examples, the height Hof the peaksmay be greater than approximately 10.5 millimeters or may be less than approximately 10.5 millimeters. Further, in one example, the peaksmay have a width Wof approximately 10.5 millimeters and, in other examples, have a width Wof greater than approximately 10.5 millimeters or less than approximately 10.5 millimeters.

The valleysdefined between each of the peaksdefine a flexion anglebetween adjacent peaks. The flexion anglemay include a first flexion angle corresponding to the relaxed state of the knit infill materialand a second flexion angle corresponding to the compressed state of the knit infill material. It is generally contemplated that the first flexion angle is greater than the second flexion angle, as the peaksare spaced apart in the relaxed state as compared to the compressed state. A plurality of intermediate flexion angles may be defined between full relaxation of the knit infill materialand full constriction of the knit infill material, such that the peaksmay be angularly spaced to varying degrees depending on a vacuum drawn within the interior voidof the bladderto constrict the knit infill material. In some examples, the flexion angle, in the relaxed state, may be approximately 31.8 degrees between adjacent peaks. However, it is contemplated that the flexion anglemay be equal to approximately 31.8 degrees or less than approximately 31.8 degrees depending on the placement of the bladder. Stated differently, a distance Dbetween a respective apexof adjacent peaksmay be approximately 11 millimeters. However, depending on the configuration and flexion angle, the distance Dbetween each apexmay be greater than approximately 11 millimeters or may be less than approximately 11 millimeters.

The valleysalso include a hinge pointat which the peaksflex or hinge between the relaxed state and the compressed state. The biasing of the apexand the hinge pointof the valleys, in combination with the flexion angle, is configured to minimize elongation of the knit infill materialin the compressed state. The knit infill materialbiases at the apexand hinge pointof the peaksand valleys, respectively, as a fluid is removed from the bladderto generally define a vacuum.

With particular reference to, operation of the bladderand associated infill materialwill be described in detail. While the bladderwill be described and shown in conjunction with the footwearof, the bladdercould be used in conjunction with an article of apparel. Further,show another example of an article of footwearincluding the bladderdisposed within a throatof the footwear. Operation of the bladderis similar to operation of the bladder. Accordingly, operation of the bladderis foregone.

When the bladderis in the relaxed state, the interior voidis at substantially atmospheric pressure. Accordingly, the resilient nature of the material forming the infill materialalong with the peaksand valleysof the infill material, cause the infill materialto move into the expanded state. In this position, the peaksmove away from one another until the infill materialis in the relaxed or expanded state. Because the infill materialis either fully or partially fixed for movement with the bladderor, alternatively, abuts portions of the bladder(i.e., the perimeter edgecontacting the seam), movement of the infill materialinto the expanded state likewise causes the bladderto move into the relaxed or expanded state. In this position, an opening to the article of footwearis increased, thereby facilitating entry of a wearer's foot into the footwearor removal of a wearer's foot from the footwear.