Patent Publication Number: US-10779616-B2

Title: Three-dimensional thermo-molding of footwear

Description:
FIELD 
     The described embodiments generally relate to articles of footwear and methods of making articles of footwear. In particular, described embodiments relate to articles of footwear and methods of making articles of footwear with a three-dimensional thermo-molding process. 
     BACKGROUND 
     Individuals are often concerned with the durability, weight, and/or comfort of an article of footwear. This is true for articles of footwear worn for non-performance activities, such as a leisurely stroll, and for performance activities, such as running. Durable footwear will properly function for an extended period of time. Lightweight footwear minimizes the weight an individual has to carry on his or her feet and may be comfortable for an individual. Customized footwear may increase comfort for an individual because it is tailored to the individual&#39;s foot anatomy. 
     Proper footwear should be durable, comfortable, and provide other beneficial characteristics for an individual. Therefore, a continuing need exists for innovations in footwear and fabrics used to manufacture the footwear. 
     BRIEF SUMMARY OF THE INVENTION 
     Some embodiments are directed towards a method of manufacturing an upper for an article of footwear, the method including disposing an inflatable bladder around a last; disposing a skin over the inflatable bladder, the skin including at least one of: a base layer including a low melting point thermoplastic polymer and a grid layer including a yarn composed of a low melting point thermoplastic polymer; placing the assembled last, inflatable bladder, and skin within a cavity of a mold; heating the mold to a predetermined temperature; and inflating the inflatable bladder such that the skin is pressed against an interior surface of the heated mold cavity to cause the skin to take on the shape of the internal surface of the mold cavity onto which it is pressed, thereby forming an upper for an article of footwear. 
     Some embodiments are directed to an upper for an article of footwear made by disposing an inflatable bladder around a last; disposing a skin over the inflatable bladder, the skin including at least one of: a base layer including a low melting point thermoplastic polymer and a grid layer including a yarn composed of a low melting point thermoplastic polymer; placing the assembled last, inflatable bladder, and skin within a cavity of a mold; heating the mold to a predetermined temperature; and inflating the inflatable bladder such that the skin is pressed against an interior surface of the heated mold cavity to cause the skin to take on the shape of the internal surface of the mold cavity onto which it is pressed, thereby forming an upper for an article of footwear. 
     Some embodiments are directed to a method of manufacturing an upper for an article of footwear, the method including disposing an inflatable bladder around a last; disposing a skin over the inflatable bladder, the skin including a layer including a low melting point thermoplastic polymer; placing the assembled last, inflatable bladder, and skin within a cavity of a mold; heating the mold to a predetermined temperature less than or equal to 180 degrees C.; and inflating the inflatable bladder such that the skin is pressed against an interior surface of the heated mold cavity to cause the skin to take on the shape of the internal surface of the mold cavity onto which it is pressed, thereby forming an upper for an article of footwear. 
     Some embodiments are directed towards an upper for an article of footwear, the upper including a single integrally molded skin defining a forefoot portion, a midfoot portion, and a rearfoot portion of the upper, the skin including at least one of: a base layer defining a forefoot portion, a midfoot portion, and a rearfoot portion of the upper and including a low melting point thermoplastic polymer; and a grid layer including a yarn composed of a low melting point thermoplastic polymer. 
     Some embodiments are directed towards an article of footwear including a midsole coupled to an upper, the upper including a single integrally molded skin defining a forefoot portion, a midfoot portion, and a rearfoot portion of the upper, the skin including at least one of: a base layer defining a forefoot portion, a midfoot portion, and a rearfoot portion of the upper and including a low melting point thermoplastic polymer; and a grid layer including a yarn composed of a low melting point thermoplastic polymer. 
     Some embodiments are directed towards an upper for an article of footwear, the upper including a single integrally molded skin defining a forefoot portion, a midfoot portion, and a rearfoot portion of the upper, the skin including a yarn composed of a low melting point thermoplastic polymer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES 
         FIG. 1  is an exemplary flowchart of a method according to an embodiment. 
         FIG. 2  is a perspective view of an inflatable bladder assembly according to an embodiment. 
         FIG. 3  is a cross-sectional view along the line  3 - 3 ′ in  FIG. 2 . 
         FIGS. 4A and 4B  show a multi-piece base layer according to an embodiment. 
         FIG. 5  is a single piece base layer according to an embodiment. 
         FIGS. 6A and 6B  show a multi-piece grid layer according to an embodiment. 
         FIG. 7  shows various shell layers according to various embodiments. 
         FIG. 8A  is a cross-sectional view of various layers of a skin disposed over an inflatable bladder assembly according to an embodiment.  FIG. 8B  is an enlarged cross-sectional view of various layers of a skin disposed over an inflatable bladder assembly according to an embodiment. 
         FIG. 9  is mold according to an embodiment. 
         FIGS. 10A, 10B, and 10C  are an exemplary process for three-dimensionally thermo-molding an upper according to an embodiment. 
         FIG. 11A  is a top perspective view of an upper according to an embodiment.  FIG. 11B  is a bottom perspective view of an upper according to an embodiment. 
         FIG. 12  is a bottom perspective view of an upper according to an embodiment. 
         FIG. 13  is a side view of an upper according to an embodiment. 
         FIG. 14  is a perspective view of an article of footwear according to an embodiment. 
         FIG. 15  is an exploded cross-sectional view of an article of footwear according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention(s) will now be described in detail with reference to embodiments thereof as illustrated in the accompanying drawings. References to “one embodiment”, “an embodiment”, “an exemplary embodiment”, etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. 
     An article of footwear has many purposes. Among other things, an article of footwear may serve to provide cushioning for a wearer&#39;s foot, support a wearer&#39;s foot, and protect a wearer&#39;s foot. Each of these purposes, alone or in combination, provides for a comfortable article of footwear suitable for use in a variety of scenarios (e.g., exercise and every day activities). The features of an article of footwear (e.g., shape and materials used to make footwear) may be altered to produce desired characteristics, for example, durability, support, weight, and/or breathability. 
     Durable footwear will properly function for an extended period of time and may instill a wearer&#39;s trust in specific manufacture&#39;s footwear, leading to repeat sales. Supportive footwear may protect an individual&#39;s feet from injury. For example, an article of footwear configured to provide ankle support may be prevent injury to an individual&#39;s ankle by inhibiting undue twisting of the ankle. Lightweight footwear may be conformable for an individual, and for individuals competing in an athletic activity, such as running or biking, may provide a completive edge due to the decreased weight the individual carries on his or her feet. Breathable footwear may increase comfort for an individual by wicking sweat and heat away from an individual&#39;s foot. Designing footwear having a high degree of one or more of these characteristics without detrimentally affecting other characteristics of the footwear may be desirable. 
     An article of footwear, or a portion thereof (e.g., an upper), may be configured to provide various degrees of durability, support, weight, breathability, etc. But the cost of manufacturing the article of footwear may also be a consideration. Footwear, or a portion thereof, that may be manufactured at a relatively low cost may be desirable for manufactures and consumers. Footwear that can be manufactured using a relatively small amount of resources (e.g., energy and man power), materials, and time reduces manufacturing costs and may also reduce the environmental impact of manufacturing. 
     Further, a manufacturing process that facilities the manufacture of customized footwear without increasing the complexity of the manufacturing process may be desirable. Customizing an article of footwear, or a portion thereof (e.g., an upper), for a particular individual or a group of individuals having similar foot anatomies (e.g., foot size and shape) may provide proper support and increased comfort for an individual. Also, it may allow an individual to order/buy articles of footwear customized to his or her needs. Moreover, it may allow the individual to order/buy new and/or replacement articles of footwear customized to his or her needs when desired. 
     In some embodiments, the article of footwear discussed herein may include an upper manufactured using a three-dimensional thermo-molding process. In some embodiments, the upper may be composed of one or more low melting point thermoplastic polymers. In some embodiments, the upper may be composed of a plurality of layers, each layer composed of one or more low melting point thermoplastic polymers. 
     In some embodiments, the maximum processing temperature of the three-dimensional thermo-molding processes discussed herein may be less than the melting point of the low melting point thermoplastic polymers used to form the upper. In some embodiments, the maximum processing temperature of the three-dimensional thermo-molding process may be such that the process releases little to no volatile substances (e.g., vapors created by chemical reactions such as those created during curing of a polymer). In some embodiments, the thermo-molding process may not cause a change in the chemical composition of the low melting point thermoplastic polymers used to form the upper. The use of low processing temperatures may reduce manufacturing cost and may reduce environmental impact of a manufacturing process by reducing the release of volatile substances. Further, a manufacturing process that does not rely on the occurrence of chemical reactions may result in a manufacturing process that is easier to control and reproduce. In some embodiments, the processing temperature of the three-dimensional thermo-molding process may be such that the low melting point thermoplastic polymer of a layer of the upper (e.g., the base layer) is malleable but does not fuse to the material of another layer of the upper (e.g., the yarns of a grid layer). 
     In some embodiments, the maximum processing temperature of the three-dimensional thermo-molding processes discussed herein may be greater than the softening point temperature of the low melting point thermoplastic polymers used to form the upper. The softening point temperature of a polymer may be measured using a Vicat softening point test. The use of such a temperature may allow different polymers and/or layers of polymers to bond (e.g., fuse) together during thermo-molding. Further, it may allow the different polymers and/or layers of polymers to take on the shape of a mold cavity used to form an upper. 
     In some embodiments, the maximum processing temperature of the three-dimensional thermo-molding processes discussed herein may be 180 degrees C. or less. In some embodiments, the maximum processing temperature of the three-dimensional thermo-molding processes discussed herein may be in the range of 180 degrees C. to 80 degrees C. In some embodiments, the maximum processing temperature of the three-dimensional thermo-molding processes discussed herein may be 160 degrees C. or less. In some embodiments, the maximum processing temperature of the three-dimensional thermo-molding processes discussed herein may be in the range of 160 degrees C. to 65 degrees C. 
       FIG. 1  shows an exemplary flowchart of a method of thermo-forming an upper for an article of footwear according to an embodiment. In step  102 , an inflatable bladder (e.g., inflatable bladder  220 ) may be disposed around a last (e.g., last  210 ) having a shape similar to that of a human foot (see e.g.,  FIGS. 2 and 3 ). The inflatable bladder may be made of a deformable material such as, but not limited to, rubber, silicone, and silicone room temperature vulcanization (RTV silicone). In some embodiments, the inflatable bladder may be made of an elastomeric material. 
     After disposing an inflatable bladder around a last in step  102 , a skin (e.g., skin  800 ) may be disposed over the inflatable bladder, thereby forming an assembled last, inflatable bladder, and skin in step  104  (see e.g.,  FIG. 8A ). The skin may define at least a portion of an upper for an article footwear after thermo-forming. In some embodiments, the skin may include one or more layers, where at least one of the layers includes a low melting point thermoplastic polymer. In some embodiments, each layer of the skin may include a low melting point thermoplastic polymer. For example, in some embodiments, the skin may include a base layer composed of one or more low melting point thermoplastic polymers and a grid layer including a yarn composed of one or more a low melting point thermoplastic polymers. In some embodiments, the skin may include layers composed of only low melting point thermoplastic polymers. 
     As used herein, “disposed over” means that a second layer/material is deposited, formed, or placed over a first layer/material. The contact between the second layer/material and the first layer/material may be indirect (i.e., there may be other layers between the first and second layers/materials), unless it is specified that the first layer/material is “in contact with,” “deposited on,” or the like with respect to the second layer/material. For example, a second layer/material may be described as “disposed over” a first layer/material, even though there are various layers/materials in between the first layer/material and the second layer/material. Furthermore, if a second layer/material is “disposed over” a first layer/material, the second layer/material is formed, deposited, or placed after the first layer/material (i.e., the first layer/material is present before the second layer/material is disposed over it). 
     As used herein, “low melting point thermoplastic polymer” means a thermoplastic polymer having a melting point of 200 degrees C. or less. Suitable low melting point thermoplastic polymers include, but are not limited to, low melting point polyesters, polyamides, polyethylene (PE), PE foams, polyurethane (PU) foams, and co-polymers or polymer blends including one or more these polymers. 
     As used herein, “high melting point thermoplastic polymer” means a thermoplastic polymer having a melting point of more than 200 degrees C. Suitable high melting point thermoplastic polymers include, but are not limited to, thermoplastic polyurethane (TPU), polyurethane foams, silicone, and nylon. In some embodiments, one or more layers of an upper may include a high melting point thermoplastic polymer. In some embodiments, the inclusion of a high melting point thermoplastic polymer may provide variable heating and/or partial forming of an upper. Variable heating and/or partial forming of different areas of an upper may provide different characteristics (e.g., breathability and/or thermal conductivity) to different areas of the upper. 
     In step  106 , the assembled last, inflatable bladder, and skin may be placed within a cavity of a mold (e.g., mold  900  in  FIG. 9 ). The cavity of the mold may include an interior shape corresponding to a desired shape for an upper. In step  108 , the mold may be heated to a predetermined temperature. In step  110 , the inflatable bladder may be inflated such that the skin is pressed against the interior surface of the heated mold cavity to cause the skin to take on the shape of the internal surface of the mold cavity onto which it is pressed, thereby forming an upper for an article of footwear. In this manner, the layers of the skin may be molded together, thereby forming a single integrally molded skin defining a forefoot portion, a midfoot portion, and a rearfoot portion of an upper. The skin may have a general shape corresponding to the shape of a human foot before it is pressed against the interior surface of the mold. After it is pressed against the interior surface of the mold, the skin may have a shape corresponding to an upper for a particular size of footwear (e.g., a particular length and width (size) and type of footwear (e.g., basketball shoe or football cleat)). After the skin takes on the shape of an upper, the upper may be removed from the mold and any excess material, if present, may be removed (e.g., by a cutting process). 
       FIGS. 2 and 3  show an inflatable bladder assembly  200  according to an embodiment. In some embodiments, inflatable bladder assembly  200  may include an inflatable bladder  220  disposed around a last  210  (last  210  is shown in broken lines in  FIG. 2  for illustration purposes). In some embodiments, inflatable bladder  220  may be disposed around last  210  and in direct contact with last  210 . In some embodiments, a release liner  212  may be disposed between last  210  and inflatable bladder  220 . In such embodiments, release liner  212  may facilitate air flow between last  210  and inflatable bladder  220  by preventing adhesion between last  210  and inflatable bladder  220 . Release liner  212  may be, but is not limited to, a Teflon® layer/film or a textured paper layer/film. In some embodiments, inflatable bladder  220  may have a hollow shape similar to the exterior shape of last  210  (e.g., a hollow shape corresponding to the shape of a human foot). 
     In some embodiments, inflatable bladder assembly  200  may include a connector  230 . Connector  230  may include a first end  232  coupled to inflatable bladder  220  via a coupling  234  and a second end  236  configured to couple with a pressure conduit for delivering pressurized air  238  from a pressure source  250 . Coupling  234  may create an air tight seal between first end  232  of connector  230  and inflatable bladder  220 . In some embodiments, coupling  234  may be a hose clamp. In some embodiments, inflatable bladder  220  may include a coupling configured to engage coupling  234 . For example, inflatable bladder  220  may include a male/female coupling and coupling  234  may include the corresponding female/male coupling. In some embodiments, connector  230  may include a pressure valve for regulating the pressure of pressurized air  238  pumped into inflatable bladder  220 . 
     As shown in  FIG. 3 , pressurized air  238  delivered via connector  230  may flow between inflatable bladder  220  and last  210  (see e.g., air flow  240 ). Pressurized air pumped between inflatable bladder  220  and last  210  will cause inflatable bladder  220  to expand outward from inflatable last  210  (i.e. in the direction of arrows  300  in  FIG. 3 ). In some embodiments, inflatable bladder  220  may expand symmetrically outward from last  210 . In such embodiments, inflatable bladder  220  may maintain a hollow shape corresponding to the shape of a human foot as it expands outward. As inflatable bladder  220  expands outward, it may force a skin and its layers (e.g., base layer, grid layer(s), and shell layer(s)) disposed over it outward as well. 
       FIGS. 4A and 4B  show a base layer  400  for a skin according to an embodiment. Base layer  400  may be configured (i.e., sized and shaped) to define at least a portion of a forefoot portion, midfoot portion, and rearfoot portion of an upper. Base layer  400  may include a peripheral section  410  and a bottom section  450 . Peripheral section  410  may be sized and shaped to form the medial portion, lateral portion, and heel portion of base layer  400 . Bottom section  450  may be sized and shaped to form the bottom portion of base layer  400 . Peripheral section  410  and bottom section  450  may be composed of one or more low melting point thermoplastic polymers. 
     In some embodiments, peripheral section  410  may be a single integrally formed piece of material. In some embodiments, bottom section  450  may be a single integrally formed piece of material. In some embodiments, the integrally formed piece(s) of material may be cut from a source material by a single cutting operation (e.g., a single die cutting or laser cutting operation). In some embodiments, the source material may be a sheet or roll of material. Single integrally formed pieces of material that are cut by a single cutting operation may facilitate efficient and reproducible manufacturing of uppers for footwear. Moreover, such manufacturing may reduce waste by reducing waste material created during manufacturing. In some embodiments, peripheral section  410  and bottom section  450  may be coupled together to form a three-dimensional shape corresponding to the shape of a human foot before or after being disposed over an inflatable bladder (e.g., inflatable bladder  220 ). 
     In some embodiments, peripheral section  410  and bottom section  450  may be composed of the same material. In some embodiments, peripheral section  410  and bottom section  450  may be cut from the same source material. In some embodiments, peripheral section  410  and bottom section  450  may be composed of different materials. In some embodiments, the material of peripheral section  410  and/or bottom section  450  of base layer  400  may be a mechanically isotropic material. In some embodiments, the material of peripheral section  410  and/or bottom section  450  of base layer  400  may be a homogenous material. 
     When coupled together, peripheral section  410  and bottom section  450  may form a substantially mechanically isotropic base layer  400 . When coupled together, peripheral section  410  and bottom section  450  may form a substantially homogenous material layer, with the exception of the location of any seams on base layer  400  (e.g., the seam joining peripheral section  410  and bottom section  450 ). The homogenous and/or mechanically isotropic nature of base layer  400  may facilitate uniform outward expansion of base layer  400  when acted on by an inflatable bladder over which base layer  400  is disposed. This may serve to create a substantially uniform wall thickness of base layer  400  after it is expanded by an inflatable bladder. This may also serve to ensure proper positioning of layers disposed over base layer  400 . 
     Peripheral section  410  may include a heel portion  412  for defining the portion of base layer  400  that wraps around the heel of a wearer, a medial portion  414  for defining the medial side of base layer  400 , and a lateral portion  416  for defining the lateral side of base layer  400 . A top edge  420  of peripheral section  410  may define at least portion of an opening in base layer  400  through which a wearer inserts his or her foot when putting on an article of footwear including base layer  400 . Top edge  420  may include a medial toe edge  422  and a lateral toe edge  424 , which may be coupled together to define a toe end of base layer  400  when peripheral section  410  is folded into a three-dimensional shape corresponding to the shape of a human foot. Top edge  420  may also include a medial forefoot edge  426  and a lateral forefoot edge  428 , which may be coupled together to define a forefoot portion of base layer  400  when peripheral section  410  is folded into a three-dimensional shape corresponding to the shape of a human foot. Edges of peripheral section  410  may be coupled together using, for example, stitching and/or an adhesive. In some embodiments, peripheral section  410  may include an extension on top edge  420  configured to define the tongue of an upper. 
     A bottom edge  418  of peripheral section  410  may be coupled to bottom section  450 . For example, in some embodiments, bottom edge  418  may be stitched to bottom section  450  at a peripheral edge  456  of bottom section  450 . In some embodiments, bottom edge  418  may alternatively or additionally be adhered to peripheral edge  456  via an adhesive. Bottom section  450  may include a forefoot portion  452  defining a forefoot area of bottom section  450  and a rearfoot portion  454  defining a rearfoot area of bottom section  450 . 
     While  FIGS. 4A and 4B  show a base layer  400  sectioned into two pieces, base layer  400  may be sectioned into a different number of pieces that may be coupled together to form a three-dimensional shape corresponding to the shape of a human foot. As a non-limiting example, peripheral section  410  may be replaced with two sections, one defining the medial half of base layer  400  and one defining the lateral half of base layer  400 . 
       FIG. 5  shows a base layer  500  for a skin according to an embodiment. Base layer  500  may be configured (i.e., sized and shaped) to define at least a portion of a forefoot portion, midfoot portion, and rearfoot portion of an upper. Base layer  500  may include a single piece of material sized and shaped to define the medial portion  510 , lateral portion  520 , bottom portion  530  (shown in broken lines in  FIG. 5  for illustration purposes), and heel portion  540  of base layer  500 . Base layer  500  may be composed of one or more low melting point thermoplastic polymers 
     In some embodiments, base layer  500  may be single integrally formed piece of material. In some embodiments, base layer  500  may be cut from a source material by a single cutting operation (e.g., a single die cutting or laser cutting operation). In some embodiments, the source material may be a sheet or roll of material. In some embodiments, the material of base layer  500  may be a mechanically isotropic material. In some embodiments, the material of base layer  500  may be a homogenous material. 
     Edges of base layer  500  may be coupled together to form a three-dimensional shape corresponding to the shape of a human foot before or after being disposed over an inflatable bladder (e.g., inflatable bladder  220 ). When folded into a shape corresponding to the shape of a human foot, base layer  500  may form a substantially mechanically isotropic material layer. When folded into a shape corresponding to the shape of a human foot, base layer  500  may form a substantially homogenous material layer, with the exception of the location of any seams on base layer  500  (e.g., the seams joining edges of base layer  500 ). The homogenous and/or mechanically isotropic nature of base layer  500  may facilitate uniform outward expansion of base layer  500  when acted on by an inflatable bladder over which base layer  500  is disposed. 
     Medial portion  510  of base layer  500  may include a toe edge  512  and lateral portion  520  may include a top edge  522 , which may be coupled together to define a toe end of base layer  500  when base layer  500  is folded into a three-dimensional shape corresponding to the shape of a human foot. Similarly, medial portion  510  may include forefoot edge  514  and lateral portion  520  may include a forefoot edge  524 , which may be coupled together to define a forefoot portion of base layer  500  when base layer  500  is folded into a three-dimensional shape corresponding to the shape of a human foot. 
     Medial portion  510  of base layer  500  may include a rearfoot edge  516  that may couple with heel portion  540  when base layer  500  is folded into a three-dimensional shape corresponding to the shape of a human foot. In particular, rearfoot edge  516  may couple with a medial heel edge  542  of heel portion  540 . Similarly, lateral portion  520  may include a rearfoot edge  526  that may couple with heel portion  540  when base layer  500  is folded into a three-dimensional shape corresponding to the shape of a human foot. In particular, rearfoot edge  526  may couple with a lateral heel edge  544  of heel portion  540 . Edges of base layer  500  may be coupled together using, for example, stitching and/or an adhesive. 
     While  FIG. 5  shows base layer  500  cut so that particular edges are coupled together when folding base layer  500  into a three-dimensional shape corresponding to the shape of a human foot, base layer  500  may be cut in alternative ways. In other words, base layer  500  may be cut so that seams joining the edges of base layer  500  are positioned differently when base layer  500  is folded into a three-dimensional shape corresponding to the shape of a human foot. 
     In some embodiments, rather than including flat pieces(s) of material that are folded into a three-dimensional shape, the base layer for a skin may be three-dimensional piece of material. For example, the base layer may be an injection molded three-dimensional layer having a shape corresponding to the shape of a human foot. In such embodiments, the base layer may not include any seams. 
       FIGS. 6A and 6B  show a grid layer  600  for a skin according to an embodiment. Grid layer  600  may be composed of one or more low-melting point thermoplastic polymers. Grid layer  600  may include open pores defined by a lattice structure. In some embodiments, the lattice structure may be a porous layer composed of a low-melting point thermoplastic polymer. In some embodiments, the lattice structure may be a woven or non-woven structure defined by yarn. In some embodiments, grid layer  600  may include yarn composed of a low melting point thermoplastic polymer. In some embodiments, the yarn of grid layer  600  may be a low melting point thermoplastic polymer yarn. In some embodiments, the yarn of grid layer  600  may include thermoplastic polyurethane. In some embodiments, the yarn of grid layer  600  may include a polymeric fiber core (e.g., thermoplastic polyurethane fiber) coated with a low melting point thermoplastic polymer (e.g., a low melting point polyester or polyamide). In some embodiments, the yarn of grid layer  600  may be woven to form a woven grid layer  600 . 
     In some embodiments, grid layer  600  may be an anisotropic layer configured to provide one or more different characteristics to different areas of upper. In some embodiments, grid layer  600  may be a mechanically anisotropic layer. Grid layer  600  may include an open pore pattern including areas having different porosities (i.e., open pore densities) configured to provide one or more different characteristics to different areas of an upper. In embodiments including a grid layer  600  including yarn, grid layer  600  may include an open pore pattern including areas having different porosities (i.e., open pore densities) defined by the arrangement of the yarn (e.g., the weave pattern of the yarn). In some embodiments, grid layer  600  may include a pattern including areas with different yarn densities configured to provide one or more different characteristics to different areas of the upper. 
     Grid layer  600  may include open pores arranged in a specific pattern (or composition of different patterns) to provide desired characteristics, such as but not limited to, ventilation, breathability, thermal conductivity, stretchability, and strength for an upper. In some embodiments, the pattern may be non-uniform to provide varying degrees of one or more of these characteristics to a particular area or areas of an upper. In some embodiments, grid layer  600  may provide at least one of: targeted zonal strength, targeted thermal conductivity, targeted breathability, and desired stretchability. In some embodiments, the pattern of grid layer  600  may work in concert with other layers of a skin (e.g., a base layer or shell layer(s)) to provide desired characteristics. 
     In some embodiments, grid layer  600  may include a peripheral section  610  sized and shaped to form the medial portion, lateral portion, and heel portion of grid layer  600 . Peripheral section  610  may include a lattice structure  630  and open pores  632 . In some embodiments, lattice structure  630  may be defined by woven or non-woven yarn. In some embodiments, grid layer  600  may include a bottom section  650  sized and shaped to form the bottom portion of grid layer  600 . Bottom section  650  may include a lattice structure  670  and open pores  672 . In some embodiments, lattice structure  670  may be defined by woven or non-woven yarn. In some embodiments, the orientation of the yarns in lattice structures  630 / 670  of grid layer  600  may provide desired strength and/or stretchability for areas of an upper. 
     In some embodiments, lattice structure  630  of peripheral section  610  and lattice structure  670  of bottom section  650  may be composed of the same material(s). In some embodiments, lattice structure  630  of peripheral section  610  and lattice structure  670  of bottom section  650  may be composed of different material(s) (or of the same material(s), but with different mechanical characteristics (e.g., stiffness)). In some embodiments, peripheral section  610  and bottom section  650  may be pieces of material cut from the same source material (e.g., a sheet or roll of material). In some embodiments, peripheral section  610  and bottom section  650  may be pieces of material cut from different source materials. In some embodiments, peripheral section  610  and bottom section  650  may be coupled together to form a three-dimensional shape corresponding to the shape of a human foot before or after being disposed over an inflatable bladder (e.g., inflatable bladder  220 ). 
     Peripheral section  610  may include a heel portion  612  for defining the portion of grid layer  600  that wraps around the heel of a wearer, a medial portion  614  for defining the medial side of grid layer  600 , and a lateral portion  616  for defining the lateral side of grid layer  600 . A top edge  620  of peripheral section  610  may define at least portion of an opening in grid layer  600  through which a wearer inserts his or her foot when putting on an article of footwear including grid layer  600 . Top edge  620  may include a medial toe edge  622  and a lateral toe edge  624 , which may be coupled together to define a toe end of grid layer  600  when grid layer  600  is folded into a three-dimensional shape corresponding to the shape of a human foot. Top edge  620  may also include a medial forefoot edge  626  and a lateral forefoot edge  628 , which may be coupled together to define a forefoot portion of grid layer  600  when grid layer  600  is folded into a three-dimensional shape corresponding to the shape of a human foot. Edges of peripheral section  610  may be coupled together using, for example, stitching and/or an adhesive. 
     A bottom edge  618  of peripheral section  610  may be coupled to bottom section  650 . For example, bottom edge  618  may be stitched and/or adhered to bottom section  650  at a peripheral edge  656  of bottom section  650 . Bottom section  650  may include a forefoot portion  652  defining a forefoot area of bottom section  650  and a rearfoot portion  654  define a rearfoot area of bottom section  650 . 
     While  FIGS. 6A and 6B  show a grid layer  600  sectioned into two pieces, grid layer  600  may be sectioned into a different number of pieces that may be coupled together to form a three-dimensional shape corresponding to the shape of a human foot, or a portion thereof. As a non-limiting example, peripheral section  610  may be replaced with two sections, one defining the medial side of grid layer  600  and one defining the lateral side of grid layer  600 . Furthermore, in some embodiments, grid layer  600  may be a single piece of material like base layer  500 . In some embodiments, grid layer  600  may be sized and shaped to for a three-dimensional shape corresponding to a portion of the shape of a human foot. For example, grid layer  600  may be sized and shaped to form a three-dimensional shape corresponding to a midfoot portion and a heel portion of a human foot. 
     In some embodiments, the lattice structure(s) of grid layer  600  (e.g., woven yarns) may be at least partially embedded within a matrix material. For example, lattice structure  630  of peripheral section  610  may be at least partially embedded within a matrix material  634  and lattice structure  670  of bottom section  650  may be at least partially embedded within a matrix material  674 . Matrix material  634  and matrix material  674  may be the same or different. In some embodiments, the lattice structure(s) of grid layer  600  may be at least partially embedded within a base layer. In other words, the material of a base layer may include a grid layer embedded at least partially therein. In such embodiments, a combined base and grid layer may be cut from source material including a base layer serving as the matrix for a grid layer. 
       FIG. 7  shows various shell layers  700  for skins according to various embodiments. Shell layers  700  may be composed of one or more low-melting point thermoplastic polymers. Shell layers  700  may be configured to provide one or more different characteristics to different areas of an upper. 
       FIG. 7  shows a heel shell layer  710 , a top medial shell layer  720 , a top lateral shell layer  730 , a bottom medial shell layer  740 , and a bottom lateral shell layer  750 . The size and shape of shell layers  710 ,  720 ,  730 ,  740 , and  750  shown in  FIG. 7  are exemplary (see e.g., shell layers in  FIGS. 12, 13, and 14  for other exemplary shapes). Shell layers  700  may be sized and shaped to cover various areas on an upper and provide such areas with desired characteristics. A skin may include any suitable number of shell layers  700 . In some embodiments, different shell layers  700  may partially or fully overlap to provide desired characteristics to areas of an upper. In some embodiments, a shell layer  700  may be sized and shaped to cover the entirety of an upper (e.g., a shell layer  700  may have the same size and shape as base layer  400  or  500 ). In some embodiments, a shell layer  700  that covers the entirety of an upper may be disposed over all other layers of a skin to protect the other layers and prevent them from detaching during use. 
     In some embodiments, shell layers  700  may be configured to provide targeted strength and/or support for an upper. For example, heel shell layer  710  may provide additional support for a wearer&#39;s ankle. As another example, bottom medial shell layer  740  and a bottom lateral shell layer  750  may provide increased strength for an upper at locations corresponding to the proximal heads of an individual&#39;s metatarsals. Such locations may experience a large amount of stress during an athletic activity (e.g., when an individual cuts to the left or right). In some embodiments, shell layers  700  may be configured to provide targeted comfort and/or protection for an individual&#39;s feet. For example, heel shell layer  710  may be composed of a low melting point thermoplastic foam configured to provide additional cushioning for an individual&#39;s heel. As other example, top medial shell layer  720  and a top lateral shell layer  730  may be composed of a low melting point thermoplastic foam configured to provide additional cushioning and protection for the sides of an individual&#39;s feet. In some embodiments, the foam of shell layers may provide increased thermal insulation for areas of an individual&#39;s feet. 
     In some embodiments, the absence of shell layers on areas of an upper may provide desired characteristics for certain areas of an upper. For example, an upper may devoid of shell layers  700  at areas corresponding to areas of an individual&#39;s feet which experience the highest skin temperature and/or sweat production during an athletic activity. The absence of shell layers  700  at these locations may provide increased thermal conductivity and/or breathability at these locations. Areas of feet that may experience the highest skin temperature and/or sweat production are described in U.S. Pat. No. 8,910,313, which is incorporated herein in its entirety by reference thereto. In some embodiments, a shell layer  700  may include an open pore pattern as discussed in regards to grid layer  600  to provided desired characteristics to areas of an upper. In some embodiments, grid layer  600  and shell layers  700  may provide an upper with a desired texture and/or aesthetically appealing design or pattern. In some embodiments, shell layer(s)  700  may provide increased traction to portions of an article of footwear. 
     In some embodiments, shell layer(s)  700  may be employed to produce partial forming and/or variable heating of an upper. For example, a shell layer disposed on a forefoot portion of an upper and comprising an insulating material may heat at a slower rate compared to a different portion of an upper (e.g., a heel portion). The variable heating may result in less bonding between layers in the forefoot portion of the upper compared to the bonding of layers in the heel portion of the upper. Variation in the amount of bonding between layers on an upper may result in variable characteristics, such as breathability and thermal conductivity, for different portions of an upper. 
       FIG. 8A  shows a skin  800  disposed over inflatable bladder  220  according to an embodiment. Skin  800  may include a base layer  810  (i.e., an innermost layer) disposed over inflatable bladder  220 . A grid layer  820  may be disposed over base layer  810 . In some embodiments, grid layer  820  may be in direct contact with base layer  810 . Skin  800  may also include one or more shell layers  830  disposed over grid layer  820 . In some embodiments, shell layer(s)  830  may be in direct contact with grid layer  820 . In some embodiments, the order of grid layer  820  and shell layers  830  may be reversed (i.e., grid layer  820  may be disposed over shell layers  830 ). In some embodiments, skin  800  may include a plurality of grid layers  820 . In some embodiments, one or more grid layers  820  may be disposed over shell layer(s)  830  and one or more grid layers  820  may be disposed between base layer  810  and shell layer(s)  830 . In some embodiments, a low tact adhesive may be used to properly position grid layer(s)  820  and/or shell layer(s)  830  over base layer  810 . 
     In some embodiments, as shown for example in  FIG. 8B , grid layer  820  may include yarn  822  including a core  826  and a coating  824 . In some embodiments, core  826  may be a polymeric fiber core. In some embodiments, core  826  may be composed of a high melting point thermoplastic polymer (e.g., thermoplastic polyurethane fiber). In some embodiments, coating  824  may be composed of a low melting point thermoplastic polymer (e.g., a low melting point polyester or polyamide). In embodiments including a coating  824  composed of a low melting point thermoplastic polymer, coating  824  may facilitate the bonding of yarn  822  to other layers (e.g., base layer  810  and/or shell layer(s)  830 ) during thermo-molding. 
       FIG. 9  shows a mold  900  for thermo-forming an upper according to an embodiment. Mold  900  may include a medial mold plate  910  including a medial mold cavity  912 . Medial mold cavity  912  may have a medial mold cavity surface  914  having a shape corresponding to the shape of a medial half of an upper for an article of footwear. Mold  900  may also include a lateral mold plate  920  including a lateral mold cavity  922 . Lateral mold cavity  922  may have a lateral mold cavity surface  924  having a shape corresponding to the shape of a lateral half of an upper for an article of footwear. 
     Together, medial mold cavity  912  and lateral mold cavity  922  may form a mold cavity having an interior shape corresponding to an upper for an article of footwear. The mold cavity may have an interior shape corresponding to an upper for various types of footwear, including but not limited to, a running shoe, a hiking shoe, a water shoe, a training shoe, a fitness shoe, a dancing shoe, a biking shoe, a tennis shoe, a cleat (e.g., a baseball cleat, a soccer cleat, or a football cleat), a basketball shoe, a boot, a walking shoe, a casual shoe, or a dress shoe. 
     As shown, for example, in  FIGS. 10A and 10B , mold  900  may be assembled around skin  800  on inflatable bladder  220  (i.e., skin  800  and inflatable bladder  220  may be inserted into the mold cavity of mold  900 ). In some embodiments, the mold cavity of mold  900  may be coated with a non-stick material, such as but not limited to a silicone spray, to reduce potential adhesion between skin  800  and the mold cavity during forming. Before or after skin  800  and inflatable bladder  220  are inserted into the mold cavity, mold  900  may be heated to a predetermined temperature. The temperature of mold  900  may be such that it softens skin  800  to allow it to take on the shape of upper for an article of footwear. In some embodiments, the predetermined temperature may be below the melting point of the low melting point thermoplastic polymers of skin  800 . In some embodiments, the predetermined temperature may be 180 degrees C. or less. In some embodiments, the predetermined temperature may be in the range of 180 degrees C. to 80 degrees C. In some embodiments, the predetermined temperature may be 160 degrees C. or less. In some embodiments, the predetermined temperature may be in the range of 160 degrees C. to 65 degrees C. In some embodiments, the predetermined temperature may be selected such that materials of skin  800  undergo no chemical reactions during thermo-forming an upper. Heat may be applied to mold  900  in one or more ways, such as but not limited to, high frequency heating. 
     After heating mold  900 , inflatable bladder  220  may be expanded to press skin  800  into contact with the interior surface of the mold cavity defined by medial mold cavity  912  and lateral mold cavity  922 . The combination of pressure and heat will cause skin to take on the shape of the interior surface of the mold cavity, thereby taking on the shape of an upper for an article of footwear. The layers of skin  800  closest to the interior surface of the mold cavity may experience the most about of heat, while the layers of skin furthest from the interior surface of the mold cavity (i.e., a base layer) may experience the least of amount of heat. In some embodiments, the material of base layer  810  may have a lower melting temperature than the materials of the other layers of skin  800 . In some embodiments, the pressing of skin  800  against the mold cavity may result in grid layer  820  becoming partially embedded within base layer  810  and/or shell layer(s)  830 . In other words, the material of base layer  810  and/or shell layer(s)  830  may at least partially fill open pores of grid layer  820 . The temperature at which, pressure at which, and/or amount of time skin  800  is pressed against the interior shape of the mold cavity may be tailored to produce an upper having desired characteristics. 
     The mold cavity of mold  900  may be sized and shaped for a particular foot type and size (i.e., length and width). In some embodiments, the mold  900  may be a customized mold including a customized interior mold cavity surface. In some embodiments, mold  900  may be customized for a particular individual. In some embodiments, mold  900  may include a mold cavity created by digitally scanning a human foot. In some embodiments, mold  900  may include a customized mold cavity created by digitally scanning an individual&#39;s foot. In some embodiments, an individual&#39;s foot may be scanned using a CREAFORM Go!SCAN 3D scanner, Serial No: 570489, manufactured by Ametek Ultra Precision Technologies. 
     When thermo-forming of uppers for footwear as discussed herein, only mold(s)  900  may need to be interchanged to form different sizes, shapes, and/or types of uppers. The interchangeability and modularity of molds may reduce manufacturing costs by reducing the number of parts that need to changed/adjusted when forming uppers for different articles of footwear. Reducing the parts that need to changed/adjusted when forming uppers for different articles of footwear may facilitate the use of an automated process for thermo-forming uppers for articles of footwear. Further, it may facilitate cost-effective manufacturing of customized uppers. 
     As shown for example in  FIG. 10C , after skin  800  takes on the shape of the mold cavity defined by medial mold cavity  912  and lateral mold cavity  922 , inflatable bladder  220  may be deflated and an upper  1000  may be removed from the mold cavity. In some embodiments, excess material may be removed (e.g., cut) from upper  1000  to define the edges of upper  1000 . 
       FIGS. 11A and 11B  show an upper according to an embodiment. As shown for example in  FIG. 11A , upper  1100  includes a forefoot end  1102 , a heel end  1104 , a medial side  1106 , and a lateral side  1108  opposite medial side  1106 . Also as shown in  FIG. 11A , upper  1100  includes a forefoot portion  1110 , a midfoot portion  1112 , and a heel portion  1114 . Portions  1110 ,  1112 , and  1114  are not intended to demarcate precise areas of upper  1100 . Rather, portions  1110 ,  1112 , and  1114  are intended to represent general areas of upper  1100  that provide a frame of reference. 
     In some embodiments, upper  1100  may include a base layer  1120  and a grid layer  1130 . Base layer  1120  may be the same as or similar to base layer  400  or  500 . Grid layer  1130  may be the same as or similar to grid layer  600 . For example, as shown in  FIGS. 11A and 11B , grid layer  1130  may include a peripheral section  1140  coupled to a bottom section  1142  at a seam  1144  (e.g., via stitching and/or an adhesive). Peripheral section  1140  may wrapped about bottom section  1142 , folded, and coupled at seam  1136  to form forefoot end  1102  and forefoot portion  1110  of upper  1100 . 
     In some embodiments, grid layer  1130  may include yarns  1132  arranged in a pattern comprising open pores  1134 . In some embodiments, grid layer  1130  may include yarns  1132  woven in a pattern comprising open pores  1134 . Open pores  1134  may have varying size and/or pore density at different areas on upper  1100  to provide different characteristics to those areas. For example, as shown in  FIGS. 11A and 11B , the pore size of pores  1134  may larger and the pore density of pores  1134  may be less in forefoot portion  1110  and heel portion  1114  of upper  1100  compared to midfoot portion  1112  of upper  1100 . In such embodiments, upper  1100  may have greater breathability and stretchability in forefoot portion  1110  and heel portion  1114  compared to midfoot portion  1112 . In such embodiments, the smaller pore size and higher pore density in midfoot portion  1112  may result in higher strength and less breathability in midfoot portion  1112  of upper  1100 . 
     In some embodiments, the orientation of yarns  1132  may provide directional strength and/or stability to upper  1100 . For example, some yarns  1132  of upper  1100  may be oriented such that they extend substantially vertically between a top edge  1141  of peripheral section  1140  and bottom section  1142  in heel portion  1114  and midfoot portion  1112  of upper  1100 . This orientation of yarns  1132  may provide vertical strength and stability for upper  1100  in heel portion  1114  and midfoot portion  1112  to vertically support a wearer&#39;s ankle and inhibit the ankle form excessively twisting during an athletic activity. 
       FIG. 12  shows an upper  1200  according to an embodiment. Similar to upper  1100 , upper  1200  includes a forefoot end  1202 , a heel end  1204 , a medial side  1206 , and a lateral side  1208  opposite medial side  1206 . Upper  1200  also includes a forefoot portion  1210 , a midfoot portion  1212 , and a heel portion  1214 . Portions  1210 ,  1212 , and  1214  are not intended to demarcate precise areas of upper  1200 . Rather, portions  1210 ,  1212 , and  1214  are intended to represent general areas of upper  1100  that provide a frame of reference. 
     In some embodiments, upper  1200  may include a base layer  1220  and a grid layer  1230 . Base layer  1220  may be the same as or similar to base layer  400  or  500 . Grid layer  1230  may be the same as or similar to grid layer  600 . For example, grid layer  1230  may include a peripheral section  1240  coupled to a bottom section  1242 . 
     In some embodiments, upper  1200  may include an ankle shell layer  1250 , a heel shell layer  1252 , and a metatarsal shell layer  1254 . Ankle shell layer  1250  may provide increased support and/or protection for a wearer&#39;s ankle. Heel shell layer  1252  may provide additional strength for upper  1200  around a wearer&#39;s heel. Metatarsal shell layer  1254  may provide additional strength for upper  1200  at locations corresponding to the proximal head of an individual&#39;s first metatarsal (i.e., an individual&#39;s medial-most metatarsal). 
       FIG. 13  shows an upper  1300  according to an embodiment. Upper  1300  may include a base/grid layer  1320 . Base/grid layer  1320  may include a base layer the same as or similar to base layer  400  or  500  and a grid layer the same as or similar to grid layer  600 . In some embodiments, upper  1300  may include a rearfoot shell layer  1340 , a top metatarsal shell layer  1342 , and a bottom metatarsal shell layer  1344 . In some embodiments, rearfoot shell layer  1340  may include an open pore layer like grid layer  600  (e.g., a woven layer) configured to provide increased support and/or protection for a wearer&#39;s ankle. Top metatarsal shell layer  1342  may provide additional strength for upper  1300  at a location corresponding to the proximal head an individual&#39;s fifth metatarsal (i.e., an individual&#39;s lateral-most metatarsal). Bottom metatarsal shell layer  1344  may provide additional cushioning for upper  1300  at a location corresponding to the proximal head of an individual&#39;s fifth metatarsal. 
     In some embodiments, upper  1300  may include a tongue  1350 . In some embodiments, tongue  1350  may be defined by a portion of a skin used to thermo-form upper  1300 . In some embodiments, tongue  1350  may be integrally formed with a layer of the skin (e.g., the base layer of the skin). In some embodiments, tongue  1350  may be coupled to the skin (e.g., via stitching and/or an adhesive) before thermo-forming. In some embodiments, tongue  1350  may be composed of a low melting point thermoplastic polymer. In some embodiments, tongue  1350  may be coupled to upper  1300  after it is thermo-molded. 
     In some embodiments, upper  1300  may include a sole wrap  1360 . Sole wrap  1360  may be configured to facilitate the attachment of a sole to upper  1300 . In some embodiments, sole wrap  1360  may include a sheet of material that may be disposed over at least a portion of a sole and bonded to the sole (see e.g., sole wrap  1516  in  FIG. 15 ). In some embodiments, sole wrap  1360  may comprise a tape that provides traction, such as an athletic tape. In some embodiments, sole wrap  1360  may be the same as or similar to the second sole element discussed in U.S. application Ser. No. 14/683,616, filed Apr. 10, 2015, the disclosure of which is hereby incorporated by reference in its entirety by reference thereto. In some embodiments, sole wrap  1360  may be a separate layer coupled to upper  1300  using stitching, an adhesive, and/or thermo-molding. In some embodiments, sole wrap  1360  may be an integral part of one or more layers (e.g., base layer, grid layer, or shell layer) of upper  1300  (i.e. sole wrap  1360  may be an integral part of the skin of upper  1300 ). 
     In some embodiments, sole wrap  1360  may be disposed over a sole before the sole and a skin (e.g., skin  800 ) are inserted into a mold cavity of a (e.g., mold  900 ). In such embodiments, the sole may be three-dimensionally shaped along with the skin of upper  1300  in a single thermo-molding operation. In some embodiments, sole wrap  1360  and a sole may be coupled to upper  1300  in a second processing operation (e.g., a second thermo-molding operation) after a skin (e.g., skin  800 ) is three-dimensionally shaped into upper  1300  in a first thermo-molding operation. 
       FIG. 14  shows an article of footwear  1400  according to an embodiment. Article of footwear  1400  may include an upper  1410  coupled to a midsole  1430 . Upper  1410  may include a body  1412  formed using a thermo-molding process discussed herein. For example, body  1412  may include a heel shell layer  1420  and a forefoot shell layer  1422 . In some embodiments, a top edge of body  1412  may be lined with a cushioning liner  1414  to provide comfort for an individual&#39;s foot. In some embodiments, body  1412  may include shoe lace eyelets  1416  for a shoe lace. 
     In some embodiments, article of footwear  1400  may include an outsole  1432  coupled to midsole  1430 . Suitable materials for midsole  1430  and outsole  1432  include, but are not limited to, a foam, a rubber, ethyl vinyl acetate (EVA), expanded Thermoplastic polyurethane (eTPU), Thermoplastic rubber (TPR) and a thermoplastic polyurethane (PU). In some embodiments, the foam may comprise, for example, an EVA based foam or a PU based foam and the foam may be an open-cell foam or a closed-cell foam. In some embodiments, midsole  1430  and/or outsole  1432  may comprise elastomers, thermoplastic elastomers (TPE), foam-like plastics, and gel-like plastics. In some embodiments, article of footwear  1400  may include a toe guard  1440 . In some embodiments, article of footwear  1400  may include a tongue  1450 . 
       FIG. 15  shows an exploded cross-sectional view of an article of footwear  1500  including an upper  1510  having a sole wrap according to an embodiment. As shown in  FIG. 15 , upper  1510  may include a first layer  1512  and a second layer  1514  defining a sole wrap  1516  disposed over at least a portion of a sole  1520 . In some embodiments, second layer  1514  may be disposed over all or a portion of first layer  1512 . In some embodiments, first layer  1512  may be a base layer as discussed herein. In such embodiments, second layer  1514  may be a grid layer or a shell layer as discussed herein. In some embodiments, first layer  1512  may be a skin comprising multiple layers as discussed herein. In such embodiments, second layer  1514  may be a separate layer disposed over at least a portion of first layer  1512 . In some embodiments, second layer  1514  may be attached to first layer  1512  by stitching, an adhesive, and/or thermo-molding. In some embodiments, article of footwear  1500  may include multiple second layers  1514  defining multiple sole wraps  1516 . 
     In some embodiments, sole  1520  may be a midsole. In some embodiments, article of footwear  1500  may include an outsole  1530  coupled to sole wrap  1516 . Suitable materials for sole  1520  and outsole  1530  include, but are not limited to, a foam, a rubber, ethyl vinyl acetate (EVA), expanded Thermoplastic polyurethane (eTPU), Thermoplastic rubber (TPR) and a thermoplastic polyurethane (PU). In some embodiments, the foam may comprise, for example, an EVA based foam or a PU based foam and the foam may be an open-cell foam or a closed-cell foam. In some embodiments, sole  1520  and/or outsole  1530  may comprise elastomers, thermoplastic elastomers (TPE), foam-like plastics, and gel-like plastics. 
     Second layer  1514  may be arranged to at least partially cover sole  1520  to provide at least one of stability, support, and bending and torsional stiffness for article of footwear  1500 . By disposing second layer  1514  over at least a portion of sole  1520 , sole  1520  may be provided with increased stability and/or stiffness. In some embodiments, sole  1520  may be fully contained in second layer  1514 . In some embodiments, sole  1520  may be partially exposed through second layer  1514 . In some embodiments, second layer  1514  may be configured to provide increased traction to portions of article of footwear  1500 . 
     In some embodiments, second layer  1514  may cover the bottom side, medial and lateral sides, and the forefoot and heel portions of sole  1520 . In some embodiments, second layer  1514  may cover sole  1520  only partially. For example, second layer  1514  may cover only a forefoot portion, a midfoot portion, or a heel portion of sole  1520 . As another example, second layer  1514  may cover only the lateral side, only the medial side, or both sides of sole  1520 . Also, the mentioned portions may be only covered partially by second layer  1514 . In some embodiments, second layer  1514  may completely cover sole  1520  and sole  1520  may be fully surrounded by second layer  1514 . In some embodiments, second layer  1514  may specifically cover portions of sole  1520  where certain characteristics are desired, such as stability, torsional and/or bending stiffness, traction, friction, etc. 
     In some embodiments, second layer  1514  may comprise yarns. The yarns may be based on natural or manmade fibers including polyester, high tenacity polyester, polyamide, metal yarns, stretch yarns, carbon yarns, glass yarns, polyethylene or polyolefin yarns, bi-component yarns, polytetrafluoroethylene (PTFE) yarns, ultra-high-molecular-weight polyethylene yarns, liquid crystal polymer yarns, specialty decorative yarns or reflective yarns or any of these yarns coated with EVA hot melt, TPU, PU, rubber or otherwise coated with a polymer. 
     In some embodiments, second layer  1514  may comprise a textile material. For example, the textile material may be a knit textile (warp or weft knit), a braided material, a woven fabric, created by tailor fiber placement, etc. In some embodiments, the textile material may be a non-woven fabric made from suitable fibers. In some embodiments, second layer  1514  may comprise at least one first area with less stretch than an adjacent area. Second layer  1514  may further comprise at least one second area with more stiffness than an adjacent area, and/or at least one third area with more traction than an adjacent area, and/or at least one fourth area with a looser knit structure than an adjacent area, and/or at least one fifth area where the second sole element is thicker than in an adjacent area. 
     Some embodiments may include a method of manufacturing an upper for an article of footwear, the method including disposing an inflatable bladder around a last; disposing a skin over the inflatable bladder, the skin including at least one of: a base layer including a low melting point thermoplastic polymer and a grid layer including a yarn composed of a low melting point thermoplastic polymer; placing the assembled last, inflatable bladder, and skin within a cavity of a mold; heating the mold to a predetermined temperature; and inflating the inflatable bladder such that the skin is pressed against an interior surface of the heated mold cavity to cause the skin to take on the shape of the internal surface of the mold cavity onto which it is pressed, thereby forming an upper for an article of footwear. 
     In any of the various embodiments discussed herein, the predetermined temperature of the mold may be below a melting point of the low melting point thermoplastic polymers of the base layer and the grid layer. In any of the various embodiments discussed, herein the predetermined temperature may be 180 degrees C. or less. 
     In any of the various embodiments discussed herein, the low melting point thermoplastic polymers of a base layer and a grid layer may be selected from the group of: polyesters, polyamides, polyethylene, polyethylene foams, polyurethane foams, co-polymers thereof, and polymer blends thereof. 
     In any of the various embodiments discussed herein, a skin may include a base layer and the base layer may be a substantially mechanically isotropic material. In any of the various embodiments discussed herein, a skin may include a base layer and the base layer may be a substantially homogenous material. 
     In any of the various embodiments discussed herein, a skin may include a base layer and a grid layer and the grid layer may be disposed over the base layer. 
     In any of the various embodiments discussed herein, a skin may include a grid layer and the yarn of the grid layer may include thermoplastic polyurethane. In any of the various embodiments discussed herein, a skin may include a grid layer and the yarn of the grid layer may be woven and include a woven pattern having areas with different yarn densities configured to provide one or more different characteristics to different areas of an upper. In any of the various embodiments discussed herein, a skin may include a grid layer and the grid layer may include a pattern having areas with different open pore densities configured to provide one or more different characteristics to different areas of the upper. 
     In any of the various embodiments discussed herein, a skin may include a base layer and disposing the skin over an inflatable bladder may include disposing one or more shell layers including a low melting point thermoplastic polymer over at least a portion of the base layer. In any of the various embodiments discussed herein, a skin may include a grid layer and disposing the skin over an inflatable bladder may include disposing one or more shell layers including a low melting point thermoplastic polymer over at least a portion of the grid layer. 
     In any of the various embodiments discussed herein, a method of manufacturing an upper for an article of footwear may include disposing a release liner between an inflatable bladder and a skin. 
     In any of the various embodiments discussed herein, a method of manufacturing an upper for an article of footwear may include a mold that is a customized mold including a customized interior surface. In any of the various embodiments discussed herein, a mold may be a customized mold including a customized interior surface for a particular individual. In any of the various embodiments discussed herein, a mold may be a customized mold including a customized interior surface for a particular foot type and size. In any of the various embodiments discussed herein, a customized mold may be created by digitally scanning an individual&#39;s foot. 
     In any of the various embodiments discussed herein, a method of manufacturing an upper for an article of footwear may include deflating an inflatable bladder and removing the upper from a mold cavity. In any of the various embodiments discussed herein, a method of manufacturing an upper for an article of footwear may include cutting the upper to remove excess material. 
     Some embodiments may include an upper for an article of footwear made by disposing an inflatable bladder around a last; disposing a skin over the inflatable bladder, the skin including at least one of: a base layer including a low melting point thermoplastic polymer and a grid layer including a yarn composed of a low melting point thermoplastic polymer; placing the assembled last, inflatable bladder, and skin within a cavity of a mold; heating the mold to a predetermined temperature; and inflating the inflatable bladder such that the skin is pressed against an interior surface of the heated mold cavity to cause the skin to take on the shape of the internal surface of the mold cavity onto which it is pressed, thereby forming an upper for an article of footwear. 
     Some embodiments may include a method of manufacturing an upper for an article of footwear, the method including disposing an inflatable bladder around a last; disposing a skin over the inflatable bladder, the skin including a layer including a low melting point thermoplastic polymer; placing the assembled last, inflatable bladder, and skin within a cavity of a mold; heating the mold to a predetermined temperature less than or equal to 180 degrees C.; and inflating the inflatable bladder such that the skin is pressed against an interior surface of the heated mold cavity to cause the skin to take on the shape of the internal surface of the mold cavity onto which it is pressed, thereby forming an upper for an article of footwear. 
     In any of the various embodiments discussed herein, a low melting point thermoplastic polymer may be selected from the group of: polyesters, polyamides, polyethylene, polyethylene foams, polyurethane foams, co-polymers thereof, and polymer blends thereof. 
     In any of the various embodiments discussed herein, a layer including a low melting point thermoplastic polymer may include a yarn composed of a low melting point thermoplastic polymer. In any of the various embodiments discussed herein, a yarn may include a core composed of a high melting point thermoplastic polymer coated with a low melting point thermoplastic polymer. 
     In any of the various embodiments discussed herein, a low melting point thermoplastic polymer may have a melting point of 200 degrees C. or less. 
     Some embodiments may include an upper for an article of footwear, the upper including a single integrally molded skin defining a forefoot portion, a midfoot portion, and a rearfoot portion of the upper, the skin including at least one of: a base layer defining a forefoot portion, a midfoot portion, and a rearfoot portion of the upper and including a low melting point thermoplastic polymer; and a grid layer including of a yarn composed of a low melting point thermoplastic polymer. 
     In any of the various embodiments discussed herein, an upper may include a shell layer including a low melting point thermoplastic polymer. 
     In any of the various embodiments discussed herein, the low melting point thermoplastic polymers of a base layer and a grid layer have melting points of 200 degrees C. or less. 
     In any of the various embodiments discussed herein, a skin may include a base layer and the base layer may be a substantially mechanically isotropic material. In any of the various embodiments discussed herein, a skin may include a base layer and the base layer may be a substantially homogenous material. 
     In any of the various embodiments discussed herein, a skin may include a base layer and a grid layer and the grid layer may be at least partially embedded within the base layer. 
     In any of the various embodiments discussed herein, a skin may include a grid layer and the yarn of the grid layer may be composed of thermoplastic polyurethane. 
     In any of the various embodiments discussed herein, a skin may include a grid layer and the grid layer may include a pattern including areas with different open pore densities configured to provide one or more different characteristics to different areas of the upper. In any of the various embodiments discussed herein, the characteristics for different areas of an upper may be selected from the group of: breathability, strength, thermal conductivity, and stretchability. 
     In any of the various embodiments discussed herein, a skin may include a grid layer and the grid layer may be a woven layer. In any of the various embodiments discussed herein, a woven layer may include a woven pattern including areas with different yarn densities configured to provide one or more different characteristics to different areas of an upper. 
     In any of the various embodiments discussed herein, a skin may include a base layer and a grid layer. 
     In any of the various embodiments discussed herein, an upper may include a plurality of grid layers disposed over the base layer. In any of the various embodiments discussed herein, an upper may include a plurality of shell layers including a low melting point thermoplastic polymer disposed over a grid layer. In any of the various embodiments discussed herein, an upper may include a plurality of shell layers that provide one or more different characteristics to different areas of the upper. In any of the various embodiments discussed herein, one or more of the shell layers may be a foam layer for providing cushioning to certain areas of the upper. 
     In any of the various embodiments discussed herein, an upper may include a single integrally molded skin that defines a tongue of the upper. 
     Some embodiments may include an article of footwear including a midsole coupled to an upper, the upper including a single integrally molded skin defining a forefoot portion, a midfoot portion, and a rearfoot portion of the upper, the skin including at least one of: a base layer defining a forefoot portion, a midfoot portion, and a rearfoot portion of the upper and including a low melting point thermoplastic polymer; and a grid layer including of a yarn composed of a low melting point thermoplastic polymer. 
     In any of the various embodiments discussed herein, the midsole may be coupled to an upper by a sole wrap. In any of the various embodiments discussed herein, a sole wrap may be disposed around at least a portion of a midsole. In any of the various embodiments discussed herein, a sole wrap may be an integral part of a skin of an upper. 
     Some embodiments may include an upper for an article of footwear, the upper including a single integrally molded skin defining a forefoot portion, a midfoot portion, and a rearfoot portion of the upper, the skin including a yarn composed of a low melting point thermoplastic polymer. 
     In any of the various embodiment discussed herein, a yarn composed of a low melting point thermoplastic polymer may include a core composed of a high melting point thermoplastic polymer coated with a low melting point thermoplastic polymer. 
     In any of the various embodiments discussed herein, an upper may include a base layer defining a portion of the forefoot portion, the midfoot portion, and the rearfoot portion of the upper, the base layer including a low melting point thermoplastic polymer. 
     In any of the various embodiments discussed herein, a yarn composed of a low melting point thermoplastic polymer may be disposed over a base layer. In any of the various embodiments discussed herein, a yarn composed of a low melting point thermoplastic polymer may be at least partially embedded in a base layer. 
     It is to be appreciated that the Detailed Description section, and not the Summary and Abstract sections, is intended to be used to interpret the claims. The Summary and Abstract sections may set forth one or more but not all exemplary embodiments of the present invention as contemplated by the inventor(s), and thus, are not intended to limit the present invention(s) and the appended claims in any way. 
     The present invention(s) have been described above with the aid of functional building blocks illustrating the implementation of specified functions and relationships thereof. The boundaries of these functional building blocks have been arbitrarily defined herein for the convenience of the description. Alternate boundaries can be defined so long as the specified functions and relationships thereof are appropriately performed. 
     The foregoing description of the specific embodiments will so fully reveal the general nature of the invention(s) that others can, by applying knowledge within the skill of the art, readily modify and/or adapt for various applications such specific embodiments, without undue experimentation, without departing from the general concept of the present invention(s). Therefore, such adaptations and modifications are intended to be within the meaning and range of equivalents of the disclosed embodiments, based on the teaching and guidance presented herein. It is to be understood that the phraseology or terminology herein is for the purpose of description and not of limitation, such that the terminology or phraseology of the present specification is to be interpreted by the skilled artisan in light of the teachings and guidance. 
     The breadth and scope of the present invention(s) should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.