WO2012118980A1

WO2012118980A1 - Color changing thermoplastic polyurethane for shoes

Info

Publication number: WO2012118980A1
Application number: PCT/US2012/027296
Authority: WO
Inventors: Dale R. Bathum; Haibiao Chen
Original assignee: Crocs, Inc.
Priority date: 2011-03-01
Filing date: 2012-03-01
Publication date: 2012-09-07

Abstract

Footwear may be configured to reversibly change color in response to temperature and/or sunlight. For example, a shoe may include a sole, a vamp that is secured to the sole, and a color-changing pigment. The color-changing pigment may be applied onto at least a portion of the shoe. The color-changing pigment may be disposed within a polymeric material forming a portion of the shoe.

Description

COLOR CHANGING THERMOPLASTIC POLYURETHANE FOR SHOES

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 61/448,151 , filed on March 1 , 201 1 , which is incorporated by reference herein in its entirety for all purposes.

TECHNICAL FIELD

[0002] The disclosure pertains generally to footwear and more particularly to footwear that is configured to reversibly change color in response to temperature and/or sunlight.

BACKGROUND

[0003] A variety of footwear is known, in a variety of designs and styles. Unique appearances are desirable, including appearances that can change over time.

SUMMARY

[0004] Embodiments of the present invention include footwear that is configured to reversibly change color in response to temperature and/or sunlight. Accordingly, an illustrative but non-limiting example may be found in a shoe that includes a sole, a vamp that is secured to the sole, and a color-changing pigment. In some embodiments, the color-changing pigment may be applied onto at least a portion of the shoe. In some embodiments, the color-changing pigment may be disposed within a polymeric material forming a portion of the shoe.

[0005] Another illustrative but non-limiting example may be found in a color- changing shoe that includes a thermoplastic polyurethane forming at least a portion of the color-changing shoe and a color-changing pigment that is dispersed within the thermoplastic polyurethane.

[0006] Another illustrative but non-limiting example may be found in a method of making a color-changing shoe. A color-changing pigment is dispersed within a polymer, and the polymer is used to form a portion of the color-changing shoe.

[0007] A shoe according to embodiments of the present invention includes a sole, a vamp secured to the sole, and a color-changing pigment. [0008] The shoe of any of paragraphs [0004] to [0007], in which the color- changing pigment is disposed on the shoe as a coating.

[0009] The shoe of any of paragraphs [0004] to [0008], in which at least a portion of the shoe comprises the color-changing pigment dispersed in a polymer.

[0010] The shoe of any of paragraphs [0004] to [0009], wherein the polymer comprises a thermoplastic polyurethane.

[0011] The shoe of any of paragraphs [0004] to [0010], wherein the shoe has a first visible color under indoor lighting and a second visible color under outdoor lighting.

[0012] The shoe of any of paragraphs [0004] to [001 1 ], wherein the color- changing pigment changes from colorless to visibly colored upon exposure to incident sunlight.

[0013] The shoe of any of paragraphs [0004] to [0012], wherein the color- changing pigment comprises a photochromic material that changes color upon exposure to incident ultraviolet light.

[0014] The shoe of any of paragraphs [0004] to [0013], wherein the color- changing pigment has a first color at a first temperature and a second color at a second temperature that is different from the first temperature.

[0015] The shoe of any of paragraphs [0004] to [0014], wherein the color- changing pigment comprises a thermochromic material that changes color upon a change in temperature.

[0016] The shoe of any of paragraphs [0004] to [0015], wherein the shoe includes more than one color-changing pigment.

[0017] The shoe of any of paragraphs [0004] to [0016], wherein the shoe has a first color at a first temperature, a second color at a second temperature and a third color at a third temperature.

[0018] The shoe of any of paragraphs [0004] to [0017], wherein the color- changing pigment comprises an encapsulated micropowder.

[0019] A color changing shoe according to embodiments of the present invention includes a thermoplastic polyurethane forming at least a portion of the color changing shoe, and a color-changing pigment dispersed within the thermoplastic polyurethane.

[0020] The shoe of any of paragraphs [0004] to [0019], wherein a composition of the color-changing pigment dispersed within the thermoplastic polyurethane has a first visible color under indoor lighting and a second visible color under outdoor lighting.

[0021] The shoe of any of paragraphs [0004] to [0020], wherein the color- changing pigment has a first color at a first temperature and a second color at a second temperature that is different from the first temperature.

[0022] The shoe of any of paragraphs [0004] to [0021 ], further comprising additional color-changing pigments.

[0023] The shoe of any of paragraphs [0004] to [0022], wherein the shoe has a first color at a first temperature, a second color at a second temperature and a third color at a third temperature.

[0024] A method of making a shoe having at least a portion that changes color, according to embodiments of the present invention includes dispersing a color- changing pigment within a polymer, and using the polymer to form the at least a portion of the shoe that changes color.

[0025] The method of paragraph [0024], wherein using the polymer to form the at least a portion of the shoe that changes color comprises using the polymer to form a vamp.

[0026] The method of any of paragraphs [0024] to [0025], wherein dispersing a color-changing pigment within a polymer comprises dispersing the color-changing pigment within a thermoplastic urethane.

[0027] The method of any of paragraphs [0024] to [0026], wherein using the polymer to form the at least a portion of the shoe that changes color comprises injection molding the at least a portion of the color-changing shoe with the thermoplastic urethane.

[0028] A shoe having at least a portion that changes color, made according to the method of any of paragraphs [0024] to [0027].

[0029] While multiple embodiments are disclosed, still other embodiments of the present invention will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] FIG. 1 illustrates a perspective view of a shoe assembly according to embodiments of the present invention.

[0031] FIG. 2 illustrates a bottom view of the shoe assembly of FIG. 1 .

[0032] FIG. 3 illustrates a bottom view of a vamp according to embodiments of the present invention.

[0033] FIG. 4 illustrates a bottom view of a sole according to embodiments of the present invention.

[0034] FIG. 5 illustrates a side view of the sole of FIG. 4.

[0035] FIG. 6 illustrates a perspective view of the sole of FIG. 4.

[0036] FIG. 7 illustrates a top view of the shoe assembly of FIG. 1 .

[0037] FIG. 8 illustrates a front view of the shoe assembly of FIG. 1 .

[0038] FIG. 9-14 illustrate color changing features of a vamp in accordance with embodiments of the present invention.

[0039] While the invention is amenable to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and are described in detail below. The intention, however, is not to limit the invention to the particular embodiments described. On the contrary, the invention is intended to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION

[0040] In the following detailed description, reference is made to the

accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural changes may be made without departing from the scope of the present invention. Therefore, the following detailed description is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims and their equivalents.

[0041] Figure 1 illustrates a shoe 100 according to embodiments of the invention. While illustrated as a shoe, it will be appreciated that embodiments of the invention pertain to other forms of footwear such as sandals and flip flops. As illustrated, the shoe 100 includes a sole 102 that is inserted into a vamp 104. As seen in Figures 2 and 3, in some embodiments, the vamp 104 includes one or more apertures 106, 108 that receive portions (140, 144) of the sole 102. The vamp 104 may also include one or more sections, such as middle section 1 10, that wrap around the sole 102, for example to add support. The middle section 1 10 may include a middle section aperture 1 1 1 through which a middle section portion 1 13 of the sole 102 may extend. In other embodiments, the middle section portion does not extend into the middle section aperture 1 1 1 but may be seen through the middle section aperture 1 1 1 . The vamp 104 may be formed of a single continuous piece of thermoplastic polyurethane (TPU) or other similar materials. The vamp 104 may be formed by injection molding or by press molding. According to some embodiments, as shown in Figure 1 , the vamp 104 has an upper surface 1 12 and a lower surface 1 14. The upper surface 1 12 may include a foot opening 1 16 through which a user may insert a foot. In some embodiments, the vamp 104 includes a strap 128 formed of TPU or EVA. The ends of the strap 130, 132 may be secured, for example with rivets, to the upper surface 1 12 of the vamp 104 near the perimeter 136 of the foot opening 1 16.

[0042] As shown in Figure 3, the lower surface 1 14 may include a forefoot sole aperture 106 having an inner forefoot sole aperture perimeter 1 17, an outer forefoot sole aperture perimeter 1 18, and a lower forefoot sole aperture perimeter surface 120. The lower surface 1 14 may also include a heel sole aperture 108 having an inner heel sole aperture perimeter 122, an outer heel sole aperture perimeter 124, and a lower heel sole aperture perimeter surface 126. The forefoot sole aperture 106 and the heel sole aperture 108 may be separated by a middle section 1 10. In some embodiments, the middle section 1 10 is formed continuously with the rest of the vamp 104. In some embodiments of the present invention, the middle section 1 10 adds support to the sole 102 when inserted into the vamp 104, and/or provides a more durable mechanical connection between vamp 104 and sole 102. The middle section 1 10, in combination with the upper surface 1 12 of the vamp 104, may form a continuous band 160.

[0043] As shown in Figure 4, the sole 102 includes a forefoot portion 140, a midfoot portion 142, and a heel portion 144. The sole 102 may be formed of an EVA-based material, and the forefoot portion 140, a midfoot portion 142, and a heel portion 144 may be formed of a continuous piece of molded material. The forefoot portion 140, midfoot portion 142, and heel portion 144 may be formed by injection molding or by press molding. In some embodiments, the forefoot portion 140 includes a forefoot ridge 146, as shown in Figures 5 and 6. The forefoot ridge 146 may extend around the entire outer perimeter 148 of the forefoot portion 140 or the forefoot ridge 146 may extend over only a portion of the outer perimeter 148 of the forefoot portion 140. Similarly, the sole 102 may include a heel ridge 150. The heel ridge 150 may extend around the entire outer perimeter 152 of the heel portion 144 or the heel ridge 150 may extend over only a portion of the outer perimeter 152 of the heel portion 144. The sole 100 also includes a midfoot portion 142. In some embodiments, a midsole channel 154 is formed between the forefoot portion 140 and the heel portion 144, for example as a substantially flat section spanning the forefoot portion 140 and the heel portion 144, as illustrated in Figure 4. The midsole channel 154 receives the middle section 1 10 portion of the vamp 104, in order to assist in securing the sole 102 to the vamp 104. In other embodiments, the sole 102 may include a plurality of channels 154.

[0044] In some embodiments, the vamp 104 includes or otherwise is formed of a translucent TPU material. In those embodiments, the transparency and/or translucency of the TPU material permits the portions of the sole 102 that are covered by the vamp 104 to be visually perceived. At the same time, in some embodiments the TPU material is not perfectly transparent and may also incorporate a particular color. Nevertheless, in those embodiments the TPU material is transparent or translucent enough that the shape and/or color of the sole 102 may be identified through the TPU material. In some embodiments, the sole 102 is a different color from the vamp 104 to emphasize the transparency or translucency of the vamp 104. For example, the sole 102 may be a darker color than the TPU material of the vamp 104. A strap 128 attached to the vamp 104 may be the same color as the sole 102 but formed of the TPU material. In other embodiments, the strap 128 may be the same color as the vamp.

[0045] In some embodiments, some or all of the shoe 100 may be configured to change color in response to an external stimulus. The shoe 100 may include one or more photochromic pigments and/or one or more thermochromic pigments.

Photochromic pigments are pigments that change their absorption (and hence their visible color) in response to incident light of particular wavelengths. Thermochromic pigments are pigments that change their absorption (and hence their visible color) in response to changes in temperature. As a result, some or all of the shoe 100 may change color in response to an individual wearing the shoe 100 passing from inside to outside, or from a cool environment to a relatively warmer environment.

[0046] In some embodiments, the color-changing pigment (or pigments) may be applied to the shoe 100 as a coating that can be applied by spraying, brushing, dipping and the like. In some embodiments, the coating may be applied via typing or stamping, particularly if the coating is applied in the form of a logo or text. The logo or text may not be visible in the absence of ultraviolet light and may appear in the presence of ultraviolet light. In some embodiments, the logo or text may not be visible at a first temperature but become visible at a second temperature.

[0047] The color-changing pigment (or pigments) may be dispersed within the polymeric material forming a part of the shoe 100. In some embodiments, the color- changing pigment (or pigments) may be dispersed within the thermoplastic polyurethane forming the vamp 104 and/or the strap 128. In some embodiments, the color-changing pigment (or pigments) may be mixed together with any non color- changing pigments before being dispersed within the thermoplastic polyurethane.

[0048] The relative amounts of color-changing pigments may be varied, depending on the relative transparency of the polymer as well as to achieve a desired color intensity. In some embodiments, the thermoplastic polyurethane may include about 0.2 to about 1 weight percent of the color-changing pigment(s). In some embodiments, the thermoplastic polyurethane may include about 0.8 weight percent of the color-changing pigment(s). In some embodiments, the pigment(s) may be mixed within the thermoplastic polyurethane for at least about 5 minutes before molding the thermoplastic polyurethane, for example by injection molding.

[0049] In some embodiments, one or more photochromic pigments may be dispersed within a polymer such as TPU. A variety of photochromic pigments are available, such as those available commercially from New Prismatic Enterprise Co., Ltd. of Taiwan (e.g. those available at http://www.colorchanqe.com.tw/enqlish incorporated herein by reference), including one or more of #12 PURPLE, #13 SKY BLUE, #14 BLUE, #16 YELLOW, #17 ORANGE, #19 MAGENTA or #22 GRAY.

[0050] In some embodiments, these pigments are colorless or substantially colorless in the absence of ultraviolet light and gain color when exposed to sufficient ultraviolet light. In some embodiments, the depth or intensity of the color may be adjusted by controlling the relative amount of pigment used. In some cases, exposing the pigments to natural sunlight is sufficient to cause a reversible color change. Once the individual returns inside or otherwise removes the incident ultraviolet light, the color-changing pigment will revert to a colorless or substantially colorless state.

[0051] It will be appreciated that indoor light does include electromagnetic energy that is within the ultraviolet portion of the spectrum. In referencing herein the relative absence (indoors) or presence (outdoors) of ultraviolet light, it is intended to refer to whether or not there is sufficient ultraviolet light, either particular

wavelength(s) and/or intensity, to trigger a color change in the photochromic pigment(s).

[0052] In some embodiments, if the color-changing pigment is the only pigment dispersed within the thermoplastic polyurethane, the vamp 104 formed from the thermoplastic polyurethane may have a milky white visible appearance in the absence of ultraviolet light. In some embodiments, the thermoplastic polyurethane may include a non color-changing pigment as well as a color-changing pigment. As a result, the vamp 104 may have a first color (provided by the non color-changing pigment) in the absence of incident ultraviolet light and a second color (provided by a blending of the non color-changing pigment as well as the activated color-changing pigment) in the presence of incident ultraviolet light.

[0053] It will be appreciated that this provides a number of options for color combinations. For example, if the polymer includes a yellow pigment that is not color-changing as well as a blue pigment that is color-changing, the resulting vamp 104 may be yellow in the absence of incident ultraviolet and may turn green (blue plus yellow equals green) in the presence of incident ultraviolet light.

[0054] In some embodiments, one or more thermochromic pigments may be dispersed within the polymer. A variety of thermochromic pigments are available, such as those available commercially from New Prismatic Enterprise Co., Ltd. of Taiwan (e.g. those available at http://www.colorchange.com.tw/english incorporated herein by reference), including one or more of RED 186C, ROSE RED 238C, MAGENTA RUBINE RED C, BROWN 497C, VERMILLION 185C, ORANGE 021 C, YELLOW 387C, CHARM GREEN C, GREEN 335C, SKY BLUE 313C, TURKISH BLUE 320C, BLUE 301 U, DARK BLUE 294C, VIOLET 2728C OR BLACK 5C2X. [0055] In some embodiments, these pigments are colorless or substantially colorless at a first temperature and gain color at a second temperature. In some embodiments, the pigments are colorless or substantially colorless at a first temperature and gain color at a second temperature that is lower than the first temperature. In some embodiments, the depth or intensity of the color may be adjusted by controlling the relative amount of pigment used. In some embodiments, if the color-changing pigment is the only pigment dispersed within the thermoplastic polyurethane, the vamp 104 formed from the thermoplastic polyurethane may have a milky white visible appearance at the first temperature.

[0056] In some embodiments, the polymer may include a non color-changing pigment as well as a color-changing pigment. As a result, the vamp 104 may have a first color (provided by the non color-changing pigment) at the first temperature and a second color (provided by a blending of the non color-changing pigment as well as the activated color-changing pigment) at the second temperature.

[0057] In some embodiments, many of these thermochromic pigments are available with activation temperatures that are in the range of about 15 degrees C to about 70 degrees C. Many of the colors are available at a variety of activation temperatures and thus pigments may be chosen to perform at a desired

temperature. For example, if it is desired that the shoe 100 change color in response to body heat, or perhaps to walking from an air conditioned building outside into a warm summer day, thermochromic pigments having activation temperatures in the range of about 20 degrees C to about 30 degrees C may be chosen.

[0058] In some embodiments, several different color-changing thermochromic pigments, each having different activation temperatures, may be combined to provide multiple changing colors to the vamp 104. For example, the polymer may include a red color-changing pigment and a blue color-changing pigment. At a temperature low enough for both pigments to be colored, the polymer may appear to be purple (red plus blue equals purple). As the temperature increases, the red pigment may revert to colorless, and the polymer may appear to be blue. As the temperature increases further, the blue pigment may revert to colorless and the polymer may appear clear, white or gray unless it also includes one or more non- color changing pigments. [0059] In some embodiments, suitable photochromic pigments are also available commercially from Kelly Chemical Corporation of Taiwan. See, for example,

http://www.kellvchemical.com/enqlish/page/products/piqments/photochromic.htm incorporated herein by reference. In some embodiments, suitable thermochromic pigments are also available commercially from Kelly Chemical Corporation of Taiwan. See, for example,

http://www.kellvchemical.com/enqlish/paqe/products/piqments/thermochromic.htm incorporated herein by reference.

[0060] In some embodiments, suitable photochromic pigments may include pigments chosen from several different classes of photochromic pigments.

Illustrative but non-limiting examples include spiropyrans, spirooxazines,

diarylethenes, azobenzens, and quinones such as phenoxynaphthacene quinone.

[0061] In some embodiments, suitable thermochromic pigments may include dyes that are encapsulated with a weak acid that acts as a proton donor. Examples of dyes include but are not limited to spirolactones, fluorans, spiropyrans and fulgides. Examples of suitable weak acids include but are not limited to bisphenol A, parabens, 1 ,2,3-triazole derivatives and 4-hydroxycoumarin.

Examples

[0062] Figures 9 through 14 provide illustrative but non-limiting examples of color-changing shoes in accordance with embodiments of the present invention. Figures 10 and 1 1 illustrate a representative vamp 204 formed of a thermoplastic polyurethane in which a blue color-changing pigment is dispersed. In this Example, 0.8 weight percent of BLUE #14, available from New Prismatic Enterprise Co., Ltd. of Taiwan, is mixed into the thermoplastic polyurethane for a minimum of 5 minutes prior to forming the vamp 204.

[0063] In Figure 9, the vamp 204 has an opaque or milky-white appearance as a result of being inside a room and thus is not exposed to all of the wavelengths and intensity of ultraviolet light that is provided by natural sunlight. In this embodiment, the vamp 204 is formed of thermoplastic polyurethane and does not include any added non color-changing pigments. In Figure 10, the vamp 204 has turned light blue as a result of being taken outdoors and exposed to natural sunlight. [0064] Figures 1 1 and 12 illustrate the vamp 204 after undergoing an aging process. A portion of a vamp 304 is included as a control. The vamp 304 does not include any color-changing pigments. Figure 1 1 illustrates the vamp 204 and the vamp 304 indoors, in the absence of ultraviolet light while Figure 12 illustrates the vamp 204 and the vamp 304 outdoors in the presence of natural sunlight. By comparing Figure 1 1 to Figure 12, it can be seen that the control vamp 304 is largely unaffected by the change in incident light while the vamp 204 has turned blue in response to the incident ultraviolet light. Figures 1 1 and 12 illustrate that the color- changing pigments within the thermoplastic polyurethane are long-lasting.

[0065] Figures 13 and 14 illustrate a representative portion of a vamp 404 that includes a thermochromic pigment that provides a reversible red color. The vamp 404 is formed of a thermoplastic polyurethane in which a thermochromic color- changing pigment is dispersed. In this Example, 0.8 weight percent of RED 186C, available from New Prismatic Enterprise Co., Ltd. of Taiwan, is mixed into the thermoplastic polyurethane for a minimum of 5 minutes prior to forming or molding (e.g. by injection molding) the vamp 404.

[0066] In Figure 13, the vamp 404 exhibits a red color as a result of being cooled in a freezer. Several minutes after removal from the freezer, the red color is starting to fade, as illustrated in Figure 14.

[0067] According to some embodiments of the present invention, a shoe includes two or more different polymeric elements, each having different color change characteristics and/or different thermochromic and/or photochromic properties. According to some embodiments of the present invention, an element of a shoe, for example the vamp portion 104, includes an embedded or intermixed color change pigment (e.g. photochromic and/or thermochromic), while other portions of a shoe, for example the sole portion 102, include a color-changing pigment disposed thereon (for example, painted or coated thereon). According to such embodiments, the color change pigment of the vamp portion 104 may be the same as, or different from, the color change pigment of the sole portion 102.

[0068] In some cases, a portion of a shoe 100 may include a color change pigment, either intermixed or disposed thereon (for example, painted or coated thereon), along with a portion of the shoe 100 which does not include a color change pigment, such that one of the portions forms a trademark, logo, phrase, or design element which blends in with the color of the other portion in a first temperature or ultraviolet lighting condition, and which is differentiated from the other portion in a second temperature or ultraviolet lighting condition. For example, a white logo including thermochromic pigment may be applied to and/or embedded within a surrounding non-color-change white material, and, when the article is exposed to a temperature change, the thermochromic pigment darkens to reveal the logo in contrast against the surrounding white material. Although embodiments of the present invention have been described with respect to footwear, based on the disclosure provided herein one of ordinary skill in the art will appreciate that similar use of color change pigments may be achieved with other garments or wearable items with TPU and/or non-TPU components, including without limitation bags, hats, bracelets, backpacks, shoe accessories.

[0069] It is understood that the above description is intended to be illustrative, and not restrictive. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

[0070] Various modifications and additions can be made to the exemplary embodiments discussed without departing from the scope of the present invention. For example, while the embodiments described above refer to particular features, the scope of this invention also includes embodiments having different combinations of features and embodiments that do not include all of the described features. Accordingly, the scope of the present invention is intended to embrace all such alternatives, modifications, and variations as fall within the scope of the claims, together with all equivalents thereof.

Claims

CLAIMS What is claimed is:

1 . A shoe comprising:

a sole; a vamp secured to the sole; and a color-changing pigment.

2. The shoe of claim 1 , in which the color-changing pigment is disposed on the shoe as a coating.

3. The shoe of claim 1 , in which at least a portion of the shoe comprises the color-changing pigment dispersed in a polymer.

4. The shoe of claim 3, wherein the polymer comprises a thermoplastic polyurethane.

5. The shoe of claim 4, wherein the shoe has a first visible color under indoor lighting and a second visible color under outdoor lighting.

6. The shoe of claim 1 , wherein the color-changing pigment changes from colorless to visibly colored upon exposure to incident sunlight.

7. The shoe of claim 1 , wherein the color-changing pigment comprises a photochromic material that changes color upon exposure to incident ultraviolet light.

8. The shoe of claim 1 , wherein the color-changing pigment has a first color at a first temperature and a second color at a second temperature that is different from the first temperature.

9. The shoe of claim 8, wherein the color-changing pigment comprises a thermochromic material that changes color upon a change in temperature.

10. The shoe of claim 1 , wherein the shoe includes more than one color-changing pigment.

1 1 . The shoe of claim 10, wherein the shoe has a first color at a first temperature, a second color at a second temperature and a third color at a third temperature.

12. The shoe of claim 1 , wherein the color-changing pigment comprises an encapsulated micropowder.

13. A color changing shoe comprising:

a thermoplastic polyurethane forming at least a portion of the color changing shoe; and a color-changing pigment dispersed within the thermoplastic

polyurethane.

14. The color changing shoe of claim 13, wherein a composition of the color- changing pigment dispersed within the thermoplastic polyurethane has a first visible color under indoor lighting and a second visible color under outdoor lighting.

15. The color changing shoe of claim 13, wherein the color-changing pigment has a first color at a first temperature and a second color at a second temperature that is different from the first temperature.

16. The color changing shoe of claim 13, further comprising additional color- changing pigments.

17. The color changing shoe of claim 16, wherein the shoe has a first color at a first temperature, a second color at a second temperature and a third color at a third temperature.

18. A method of making a shoe having at least a portion that changes color, the method comprising:

dispersing a color-changing pigment within a polymer; and using the polymer to form the at least a portion of the shoe that

changes color.

19. The method of claim 18, wherein using the polymer to form the at least a portion of the shoe that changes color comprises using the polymer to form a vamp.

20. The method of claim 18, wherein dispersing a color-changing pigment within a polymer comprises dispersing the color-changing pigment within a thermoplastic urethane.

21 . The method of claim 20, wherein using the polymer to form the at least a portion of the shoe that changes color comprises injection molding the at least a portion of the color-changing shoe with the thermoplastic urethane.

22. A shoe having at least a portion that changes color, made according to the method of claim 18.