Bladder for article having a portion with a metallic layer

Abstract

The present disclosure describes an article of footwear that has a sole structure, and a bladder associated with the sole structure. The bladder includes a first layer enclosing and defining an enclosed pocket and a second layer disposed on at least a portion of the first layer. The second layer has a pigment formed at least partially of metallic flakes. In some aspects, a primer layer is included and is disposed between an outer surface of the first layer and an inner surface of the second layer. A top coat may be disposed on an outer surface of the second layer. In some aspects, a portion of the bladder is viewable from an exterior of the article of footwear, and the second layer is disposed on the first portion of the bladder. In still other aspects, the second layer is disposed on the entire outer surface of the bladder.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This non-provisional patent application claims the priority benefit of co-pending U.S. provisional application no. 63 / 743,019, filed January 8, 2025 and titled “BLADDER FOR ARTICLE HAVING A PORTION WITH A METALLIC LAYER.” The above-referenced application is incorporated herein by reference in its entirety.BACKGROUND

[0002] Fluid-filled bladders are now used in some athletic equipment, such as footwear. In some examples, air bags are used as a portion of a footwear midsole or outsole. These air bags provide a supporting and cushioning element to the footwear. Traditionally, these air bags are made from an elastomeric thermoplastic material, and are relatively clear. The material of the traditional bladders is often clear or at least translucent, but can also yellow over time. A major differentiator in footwear is the styling, or appearance, of the footwear. It would be desirable to provide bladders with a more aesthetically pleasing metallic look, and to have a variety of different looks available to the footwear designers, at least for that portion of an air bladder that is visible when the footwear is worn by a user, and that have the desired performance characteristics.BRIEF DESCRIPTION OF DRAWINGS

[0003] FIG. 1 illustrates a side view of an article of footwear having a plurality of air bladders, in accordance with the present disclosure.

[0004] FIG. 2 illustrates a perspective view of an exemplary air bladder used in the footwear of FIG. 1.

[0005] FIG. 3A illustrates a cross-sectional view of the air bladder of FIG. 2 taken along line 3A-3A in FIG. 2, in accordance with the present disclosure.

[0006] FIG. 3B illustrates a cross-sectional view of an alternative air bladder, in accordance with the present disclosure.

[0007] FIG. 4A illustrates an enlarged view of a portion of the outer edge of the air bladder of FIG. 3A, in accordance with the present disclosure.

[0008] FIG. 4B illustrates an enlarged view of an outer edge of an alternative air bladder, in accordance with the present disclosure.DETAILED DESCRIPTION

[0009] Fluid-filled bladders are now in use within articles as cushioning and support elements. For example, such bladders may be used in an article of footwear, a component of an article of footwear (such as a part of a midsole or an outsole), or other sporting equipment. The bladders are elastomeric, such that they retain their shape after repeated forces (such as by walking or running) are applied. In other words, the bladders can, upon exposure to a force, flex, expand, contract and return to the original shape upon removal of the force. Typical bladders may be made from polyurethane elastomeric materials, polyester elastomers, fluoro elastomers, polyvinyl chloride elastomers and the like. These materials are used to form a sealed bladder containing a fluid, such as a gas, and are typically clear.

[0010] The present disclosure contemplates a bladder having a layered coating that improves the appearance of the bladder (at least at the portion of the bladder exposed for viewing), without negatively affecting the performance of the bladder. These bladders, or airbags, are typically a complex curvature structure that provides opportunities for varied reactance and reflectance from the surface. This varied reactance and reflectance can provide a varied appearance while having a substantially uniform layer or coating. The bladder is subjected to deformation forces when worn by a user (such as by walking, running, etc.) that cause the bladder to deform in certain areas and to return to the same shape and condition when the deformation forces are absent. The layered coating of the present disclosure retains its structure and stays bonded to the air bladder even after repeated deformation cycles, as opposed to traditional metallic pigmented paints and coatings that are not sufficient for use in connection with the intentionally deformable structure of an airbag. The layered coating uses metallic flakes within the layer that are selected to achieve the desired resilience while still providing the desired appearance.

[0011] In some aspects, an article of footwear is provided. The article of footwear has a sole structure, and a bladder associated with the sole structure. The bladder includes a first layer defining an enclosed pocket and a second layer disposed on at least a portion of the first layer. The second layer has a pigment formed at least partially of metallic flakes. In some aspects, a primer layer (for example, a layer of thermoplastic polyurethane) is included and is disposed between an outer surface of the first layer and an inner surface of the second layer. In other aspects, a top coat (for example, a layer of thermoplastic polyurethane) is disposed on an outer surface of the second layer. In some aspects, a first portion of the bladder is viewable from an exterior of the article of footwear, and the second layer is disposed on the first portion of the bladder. In still other aspects, the second layer is disposed on the entire outer surface of the bladder. The second layer, in other aspects, is disposed on the bladder on any surface that is viewable from an exterior of the article of footwear. This specification may describe the article of footwear in an “as worn” condition, or as “in-use” which are meant to provide a context for the article relative to the viewer and are meant to convey that some or all of a portion of the exterior of the article of footwear is visible.

[0012] The metallic flakes of the second layer, in some aspects, are in a leafing format. Leafing in the context of metallic pigments refers to a phenomenon where metallic particles, such as aluminum flakes, align themselves on the surface of a coating or paint layer, forming a continuous reflective layer. This alignment occurs due to the specific formulation of the metallic pigment and the coating medium, which includes additives that encourage the particles to migrate and orient at the surface. In some aspects, the metallic flakes are oriented parallel to the coating surface, enhancing the reflective properties of the second layer (and thus the bladder or at least the viewable portion of the bladder). The orientation of the metallic flakes creates a highly reflective, mirror-like finish. Additionally, the leafing pigment layer may offer a degree of weather protection as the second layer with the metallic leafing pigment can act as a barrier to ultra-violet light and moisture.

[0013] In this leafing format, the metallic flakes, in some aspects, are nearer to an outer surface of the second layer than an inner surface of the second layer. The second layer may be disposed on an area of the bladder that is non-planar (such as a convex or concaved curved area). In some aspects, the metallic flakes may have a cylindrical or circular shape. The metallic flakes, in some aspects, are made from an aluminum alloy. The metallic flakes may have an average diameter of less than 40 microns, or be in the range of about 4-10 microns, and in some aspects, have an average diameter of about 6 microns. In some aspects, the pigment is 0.5% by weight of metallic flakes within a solvent-based solution. At least the second layer is flexible during dimensional transformation (and when used, the primer layer and the top coat are flexible during dimensional transformation). In still further aspects, the second layer may include an additional colored layer or an additional colored pigment or dye.

[0014] In some aspects, a bladder for use in an article (such as, for example, the article of footwear described above) is provided. More specifically, the bladder includes a first layer defining an enclosed pocket and a second layer disposed on at least a portion of the first layer. The second layer has a pigment formed at least partially of metallic flakes. In some aspects, a primer layer (for example, a layer of thermoplastic polyurethane) is included and is disposed between an outer surface of the first layer and an inner surface of the second layer. In other aspects, a top coat (for example, a layer of thermoplastic polyurethane) is disposed on an outer surface of the second layer. In some aspects, the primer layer, the second layer and the top coat cover the entirety of the outer surface of the first layer. In some aspects, a first portion of the bladder is viewable from an exterior when used in the article, and the second layer is disposed on the first portion of the bladder.

[0015] Positional terms used when describing the article of footwear such as front, back, inner-facing surface, outer-facing surface, upper, lower, proximal, distal, medial, lateral, and the like are with respect to the article of apparel being worn as intended with the wearer standing upright. Similarly, the outer-facing surface of the article of footwear is configured to face toward the external environment.

[0016] The term “dimensional transformation” as used herein means a change or alteration in one or more dimensions, such as in an x-direction or axis, y-direction or axis, and / or z-direction or axis. For example, an object may undergo a dimensional transformation by expanding, shrinking, folding, bending, curling, lifting, relaxing, and / or straitening along a length, width and / or height.

[0017] FIG. 1 is a side view of an article of footwear 10. The article of footwear 10 typically includes a sole structure 12 that supports an upper 14. The upper 14 facilitates the coupling of the article 10 to a user’s foot, and may include attachment mechanisms such as laces, hook and loop fasteners, and the like. The sole structure 12 may include, in some aspects, an outsole, a midsole, a strobel, and / or an insole (or some combination of these components). One or more fluid-filled bladders 16 may be associated with the sole structure 12. Each bladder 16 may be, for example, an elastomeric material surrounding and containing a fluid, such as air. As seen in FIG. 1, a portion 18 of one or more of the bladders 16 may be exposed, such that the portion 18 is visible on the exterior of the article of footwear 10. For example, portion 18A is a viewable portion of an air bladder 16A at the rear or heel end of the sole structure 12. “Viewable,” in the context of this application, means that the portion is viewable when the article is being worn by a user, or as viewed from an exterior perspective (such as on a display shelf).

[0018] FIG. 2 depicts the air bladder 16A, isolated from the sole structure 12. As can be seen, the bladder 16A may have a complex shape, with curved or radial outer surfaces 20. Bladders 16 may take any of a variety of shapes, and may have a variety of different sizes, depending on where the bladder 16 is used in the design of the article of footwear 10, and this disclosure is not limited to any particular shape or size of the bladder 16. The bladder 16 is flexible when exposed to forces to induce dimensional transformations. In the example bladder 16A of FIG. 2, a first visible portion 18A (depicted in dashed lines in FIG. 2) is positioned on one side of the bladder 16A. In aspects, a bladder 16 may have additional visible portions 18 in different parts. For example, the bladder 16B may have a second visible portion 18B positioned on an opposite side of the bladder 16A from the visible portion 18A.

[0019] FIG. 3A depicts a cross-section of the bladder 16A. Again, a bladder 16 may take a number of different shapes, and this disclosure is not limited to a bladder 16 of any particular shape. The material forming the bladder may be seen as a first layer 17. This first layer 17 refers to an inner layer or layers, and may be the innermost layer or layers of a multilayer structure. Stated differently, the first layer 17 is usually the layer or multilayer construction closest to the fluid contained in the bladder 16. This first layer 17 forming the bladder 16 may comprise, in some aspects, a composite of alternating TPU and barrier microlayers. The barrier microlayers may be individual layers of TPU or other barrier material having a thickness in the range of 100 microns. In some aspects, the material forming first layer 17 may be a polymeric composite having between 10-50 layers and thousands of microlayers. In some aspects, the TPU microlayers of the material forming the first layer 17 are formed from elastomeric thermoplastic polyurethanes, such as, for example, a polydiene polyol-based TPU.

[0020] As seen in FIGS. 2 and 3A, a bladder 16 (such as bladder 16A) may include one or more visible portions 18. The portion(s) 18 may be present on the medial side of the article of footwear 10, the lateral side, or both the medial side and the lateral side (e.g., portions 18A and 18B of bladder 16A in FIGS. 2 and 3A). In some aspects, the visible portion 18 may be present on a rear of the sole structure 12 as well. In this disclosure, the visible portion 18 may be present in any of a number of locations on the article 10. As shown, at least the visible portion 18 may have a multi-layered construction.

[0021] The visible portion 18 includes, in some aspects, a polyurethane-based primer layer 22. The primer layer 22 may be a solvent-based polyurethane coating that is applied to the outer surface of the bladder 16. In some aspects, the primer layer 22 is sprayed onto the bladder 16. In some aspects, the bladder 16 is first cleaned, and plasma treated prior to application of the primer layer 22. The primer layer 22, in some aspects, is a thermoplastic polyurethane, such as TPU-HM. The visible portion 18 also has a second, color layer 24. In some aspects, the second layer 24 is applied directly to the bladder 16 (without the primer layer 22). In some aspects, the second layer 24 includes a metallic pigment applied in a solvent-based solution. In some aspects, the layer 24 includes metallic flakes 26 as the pigment. The metallic flakes 26 can be, as one example, aluminum flakes. The use of aluminum as the pigment flakes 26 helps protect the second layer 24 from oxidizing and changing appearance and performance. Other oxides could also be used, such as titanium dioxide. The metallic flakes 26 are added to a solvent-base to form the material for the second layer 24. In some aspects, the metallic flakes 26 within the layer 24 are created using a plasma deposition technique. In some aspects, the metallic flakes 26 may be leafing or non-leafing and may include a variety of shapes. In leafing pastes or coatings, as best seen in FIG. 4A, the metallic flakes 26 in the layer 24 are typically nearer to an outer surface 28 of the layer 24 than an inner surface 30 of the layer 24, and can be more uniformly distributed in the layer 24. This can be, in part, because of the orientation and arrangement of the metallic flakes 26. In one aspect, the leafing metallic flakes 26 are formed in the shape of a circular disc. In some aspects, the metallic flakes 26 of the pigment for the layer 24 are less than 40 microns in diameter, or less than 25 microns in diameter, or less than 10 microns in diameter. In some aspects, the metallic flakes of the pigment for the layer 24 are between 4-10 microns in diameter, and in some aspects, average around 6 microns in diameter. The second layer 24, with the metallic flakes 26, provides a unique metallic-look to the visible portion 18. As compared with a non-leafing solution, the leafing flakes 26 in the layer 24 provide added reflectivity to further achieve the metallic look for the visible portion 18.

[0022] The layer 24 provides a coating composition where the amount of pigment (the leafing flakes 26) within the layer 24 is balanced to achieve an optimal combination of translucency and reflectivity. The concentration of the metallic flakes 26, expressed as a weight percentage within the solution forming the layer 24, plays a critical role in determining the visual characteristics of the visible portion 18. An increase in the pigment concentration (higher concentration of the flakes 26) enhances the reflectivity, thereby imparting a more pronounced metallic appearance to the visible portion 18. Conversely, a higher pigment concentration results in reduced translucency.

[0023] The metallic flakes 26, often composed of aluminum or mica, are integral to achieving the desired aesthetic effect in the visible portion 18. The metallic flakes 26 can vary in size and shape, with common forms including "cornflake" and "silver-dollar" geometries. The orientation of these flakes within the layer 24 influences the visual outcome. Leafing pigments, such as those treated with stearic acid, tend to move towards the outer surface of the coating, creating a continuous metallic layer that reflects light in a highly specular manner. This leafing effect is crucial for achieving a bright, reflective finish.

[0024] The visual effect of the visible portion 18 can be controlled by adjusting the ratio of pigment to solvent binder within the layer 24. In certain embodiments, a ratio of approximately 0.5% by weight of pigment flakes to the solvent binder is employed during the formation of the layer 24. This specific ratio is significantly lower than other ratios utilized in previously known colored coatings, thereby offering a unique balance of metallic sheen and translucency. The lower pigment concentration, combined with the use of leafing pigments, encourages the flakes 26 to lie flatter, that is, to orient themselves to be more parallel relative to the outer surface, as illustrated in FIG. 4A, which enhances reflectivity. Simultaneously, the flakes are sufficiently spaced apart to maintain a degree of translucency. The appropriate proportion of metallic flakes 26 within the coating layer is important in achieving the desired balance of properties. For instance, a higher concentration of flakes 26 increases reflectivity but can reduce translucency, making the coating appear more opaque. Conversely, a lower concentration of flakes 26 enhances translucency but may diminish the metallic appearance. As set forth above, in some aspects, the proportion is around 0.5% by weight, which provides a metallic look that is also somewhat translucent. This balance is achieved by ensuring the flakes 26 are relatively evenly distributed and lying flat within the coating layer, enhancing both reflectivity and translucency. This innovative approach results in a coating that provides a distinctive metallic and translucent appearance, particularly in the visible portion 18. The strategic balance of pigment concentration not only achieves the desired aesthetic effect but also represents a significant advancement over existing coating technologies.

[0025] As seen in FIG. 4A, the visible portion 18 may also include a top coat 34. In some aspects, the top coat 34 is a thermoplastic polyurethane layer on top of the second layer 24. The top coat 34 seals the pigment flakes 26 in the second layer 24. In some aspects, the top coat 34 also enhances the gloss of the visible portion 18 by normalizing the texture of the upper surface of the visible portion 18. The visible portion 18 shown in FIG. 4A thus has a primer layer 22, a second layer 24 and a top coat 34. This multi-layer construction provides a metallic appearance in the area of visible portion 18, while remaining flexible and able to withstand the compression, expansion and other movements of the bladder 16 without degradation.

[0026] In some aspects, the multi-layer construction including the metallic flakes 26 passes KIM complete testing at 320,000 cycles (and is thus suitable for many uses, including as a component in a footwear sole structure). KIM cycle testing for shoe outsoles or sole structures involves evaluating the durability and performance of the materials used in the soles. This testing method helps ensure that the outsoles or sole structures can withstand various stresses and conditions they might encounter during use (such as when worn by users). One aspect of KIM cycle testing is to assess the resilience and cushioning properties of the sole structure (such as the outsole, midsole, including the polymer foam material and any air bladders). Additionally, KIM cycle testing may involve examining the integration of different layers within the sole structure, such as the midsole, outsole, and any additional elements like fluid-filled chambers or plates that enhance stability and motion control. This comprehensive testing ensures that the sole structure provides the necessary support, comfort, and durability for the wearer.

[0027] In another aspect, an additional colorant may be added to second layer 24. The colorant is shown in FIG. 4B as an additional layer 36. In some aspects, the additional colorant can be incorporated into second layer 24, rather than as an added layer (as shown in FIG. 4B as layer 36). Any of a variety of colorants can be used as the additional colorant to provide a colored and metallic look to visible portion 18.

[0028] As shown in FIGS. 3A, 4A and 4B, the layers discussed above (primer layer 22, second layer 24 (and optionally the colorant layer 36), and the top coat 34 may be applied only in the area of visible portion(s) 18. Each of the layers (primer layer 22, second layer 24 (and optionally the colorant layer 36), and the top coat 34) may be applied with a spraying process, or by brushing or vapor deposition, for example. In other aspects, one or more of the layers may be applied using a dipping process. Further, in some aspects, as shown in FIG. 3B, the layers (primer layer 22, second layer 24 (and optionally the colorant layer 36), and the top coat 34) may be applied across the entirety of the outer surface of the bladder 16 (rather than solely in the visible portion 18). As is best seen in FIG. 2, the bladder 16 may have a complex shape, with outer convex or concave curved surfaces. By applying the metallic second (color) layer 24 to such surfaces, the reflectivity of the second layer 24 further adds to the overall appearance.

[0029] While shown in FIG. 1 as being incorporated into an article of footwear 10, the bladder 16 described above could be used on other articles, such as other pieces of clothing or other articles of sporting equipment.

[0030] The following clauses represent example embodiments of concepts contemplated herein. Any one of the following clauses may be combined in a multiple dependent manner to depend from one or more other clauses. Further, any combination of dependent clauses (clauses that explicitly depend from a previous clause) may be combined while staying within the scope of aspects contemplated herein. The following clauses are examples and are not limiting.

[0031] Clause 1. An article of footwear, comprising: a sole structure; and a bladder associated with the sole structure; the bladder comprising a first layer defining an enclosed pocket, and a second layer disposed on at least a portion of the first layer, the second layer having a pigment formed at least partially of metallic flakes.

[0032] Clause 2. The article of footwear of clause 1, further comprising a primer layer disposed between an outer surface of the first layer and an inner surface of the second layer.

[0033] Clause 3. The article of footwear of any of clauses 1-2, further comprising a top coat disposed on an outer surface of the second layer.

[0034] Clause 4. The article of footwear of any of clauses 1-3, wherein a first portion of the bladder is viewable from an exterior of the footwear, and wherein the second layer is disposed on the first portion of the bladder.

[0035] Clause 5. The article of footwear of any of clauses 1-4, wherein a second portion of the bladder is viewable from an exterior of the footwear, and wherein the second layer is disposed on the second portion of the bladder.

[0036] Clause 6. The article of footwear any of clauses 1-5, wherein the flakes are disposed within the second layer nearer to the outer surface of the second layer than the inner surface of the second layer.

[0037] Clause 7. The article of footwear of any of clauses 1-6, wherein the outer surface of the first layer in the area of the first portion is non-planar.

[0038] Clause 8. The article of footwear of any of clauses 1-7, wherein the flakes are an aluminum alloy.

[0039] Clause 9. The article of footwear of any of clauses 1-8, wherein the flakes have a generally circular shape.

[0040] Clause 10. The article of footwear of clause 9, wherein the flakes have an average diameter of less than 40 microns.

[0041] Clause 11. The article of footwear of any of clauses 9-10, wherein the flakes have a diameter in a range of 4-10 microns.

[0042] Clause 12. The article of footwear of any of clauses 9-11, wherein the flakes have an average diameter of six microns.

[0043] Clause 13. The article of footwear any of clauses 1-12, wherein the pigment is 0.5% metallic flakes by weight in a solvent-based solution.

[0044] Clause 14. The article of footwear of any of clauses 1-13, wherein the second layer is a flexible during dimensional transformation.

[0045] Clause 15. The article of footwear of any of clauses 1-14, wherein the second layer further comprises an additional colored pigment.

[0046] Clause 16. A bladder for use in an article, comprising: a first layer defining an enclosed pocket; and a second layer disposed on at least a portion of the film layer, the second layer having a pigment formed at least partially of metallic flakes.

[0047] Clause 17. The bladder of clause 16, further comprising a primer layer disposed between an outer surface of the first layer and an inner surface of the second layer.

[0048] Clause 18. The bladder of any of clauses 1-17, further comprising a top coat disposed on an outer surface of the second layer.

[0049] Clause 19. The bladder any of clauses 1-18, wherein the primer layer, the second layer and the top coat cover an entirety of the outer surface of the first layer.

[0050] Clause20. The bladder any of clauses 1-19, wherein a first portion of the bladder is viewable from an exterior of the article when in use, and wherein the second layer is disposed on the first portion of the bladder.

[0051] Clause 21. The bladder any of clauses 1-20, wherein the flakes are disposed within the second layer nearer to the outer surface of the second layer than the inner surface of the second layer.

[0052] Clause 22. The bladder any of clauses 1-21, wherein the outer surface of the bladder in the area of the first portion is non-planar.

[0053] Clause 23. The bladder of any of clauses 1-22, wherein the flakes are an aluminum alloy.

[0054] Clause 24. The bladder of any of clauses 1-23, wherein the flakes have a generally circular shape.

[0055] Clause 25. The bladder of any of clauses 1-24, wherein the flakes have an average diameter of less than 40 microns.

[0056] Clause 26. The bladder of any of clauses 1-25, wherein the flakes have a diameter in the range of 4-10 microns.

[0057] Clause 27. The bladder of any of clauses 1-26, wherein the flakes have an average diameter of six microns.

[0058] Clause 28. The bladder any of clauses 1-27, wherein the pigment is (0.5%)? metallic flakes by weight in a solvent-based solution.

[0059] Clause 29. The bladder of any of clauses 1-28, wherein the second layer is a flexible during dimensional transformation.

[0060] Clause 30. The bladder of any of clauses 1-29, wherein the second layer further comprises an additional colored pigment.

[0061] The subject matter of the present invention is described with specificity herein to meet statutory requirements. However, the description itself is not intended to limit the scope of this disclosure. Rather, the inventors have contemplated that the claimed or disclosed subject matter might also be embodied in other ways, to include different steps or combinations of steps similar to the ones described in this document, in conjunction with other present or future technologies. Moreover, although the terms “step” and / or “block” might be used herein to connote different elements of methods employed, the terms should not be interpreted as implying any particular order among or between various steps herein disclosed unless and except when the order of individual steps is explicitly stated.

[0062] Aspects of the present disclosure have been described with the intent to be illustrative rather than restrictive. Alternative aspects will become apparent to those skilled in the art that do not depart from its scope. A skilled artisan may develop alternative means of implementing the aforementioned improvements without departing from the scope of the present disclosure.

[0063] It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations and are contemplated within the scope of the claims. Not all steps listed in the various figures need be carried out in the specific order described.

Claims

1. An article of footwear, comprising:a sole structure; anda bladder associated with the sole structure;the bladder comprising a first layer defining an enclosed pocket, and a second layer disposed on at least a portion of the first layer, the second layer having a pigment formed at least partially of metallic flakes.

2. The article of footwear of claim 1, further comprising a primer layer disposed between an outer surface of the first layer and an inner surface of the second layer.

3. The article of footwear of claim 1, further comprising a top coat disposed on an outer surface of the second layer.

4. The article of footwear of claim 1, wherein a first portion of the bladder is viewable from an exterior of the footwear, and wherein the second layer is disposed on the first portion of the bladder.

5. The article of footwear of claim 4, wherein a second portion of the bladder is viewable from an exterior of the footwear, and wherein the second layer is disposed on the second portion of the bladder.

6. The article of footwear of claim 3, wherein the metallic flakes are disposed within the second layer nearer to the outer surface of the second layer than an inner surface of the second layer.

7. The article of footwear of claim 1, wherein the metallic flakes comprise an aluminum alloy.

8. The article of footwear of claim 1, wherein the metallic flakes comprise a generally circular shape.

9. The article of footwear of claim 8, wherein the metallic flakes have an average diameter of less than 40 microns.

10. The article of footwear of claim 8, wherein the metallic flakes have a diameter in a range of 4-10 microns.

11. The article of footwear of claim 1, wherein the pigment is 0.5% metallic flakes by weight in a solvent-based solution.

12. The article of footwear of claim 1, wherein the second layer is flexible.

13. A bladder for use in an article, comprising:a first layer defining an enclosed pocket; anda second layer disposed on at least a portion of the first layer, the second layer having a pigment comprising metallic flakes.

14. The bladder of claim 13, further comprising a primer layer disposed between an outer surface of the first layer and an inner surface of the second layer.

15. The bladder of claim 14, further comprising a top coat disposed on an outer surface of the second layer.

16. The bladder of claim 15, wherein the primer layer, the second layer and the top coat cover an entirety of the outer surface of the first layer.

17. The bladder of claim 15, wherein a first portion of the bladder is viewable from an exterior of the article when in use, and wherein the second layer is disposed on the first portion of the bladder.

18. The bladder of claim 15, wherein the metallic flakes are disposed within the second layer nearer to the outer surface of the second layer than an inner surface of the second layer.

19. The bladder of claim 15, wherein the metallic flakes are an aluminum alloy.

20. The bladder of claim 15, further comprising an additional layer disposed between the first layer and the second layer, the additional layer comprising a second pigment.

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