Articles of footwear, manufacturing systems, and processes for forming footwear using recycled plastics

Abstract

Presented are manufacturing systems, methods, and devices for forming footwear using scrap or waste plastic materials. A method for manufacturing an article of footwear, such as an athletic shoe, begins with receiving a batch of recycled plastic, which may include thermoplastic elastomers or ethylene-vinyl acetate, and grinding the batch of recycled plastic material. The ground recycled material is processed, for example, by adding a foaming agent that activates at elevated temperatures. The processed recycled material is placed into the internal cavity of a final mold that is shaped like a segment of the footwear, such as a unitary sole structure. To form the footwear segment, the processed recycled material is heated past the threshold activation temperature of the foaming agent such that the foaming agent causes the recycled material to expand and fill the internal cavity of the final mold. The formed footwear segment is then extracted from the mold.

What is claimed: 
     
         1 . An article of footwear for a foot of a user, the article of footwear comprising:
 an upper configured to receive the foot of the user; and   a sole structure attached to the upper and configured to support thereon the foot of the user, the sole structure having an outsole section that defines a ground-engaging portion of the footwear,   wherein an outer surface of the sole structure includes a plurality of distinctly shaped cavities, a plurality of distinctly shaped protrusions, and a plurality of distinctly shaped plastic fragments.   
     
     
         2 . The article of footwear of  claim 1 , wherein the outer surface of the sole structure is substantially covered with the distinctly shaped cavities, the distinctly shaped protrusions, and the distinctly shaped fragments. 
     
     
         3 . The article of footwear of  claim 1 , wherein the distinctly shaped cavities, the distinctly shaped protrusions, and the distinctly shaped plastic fragments are randomly dispersed on the outer surface of the sole structure. 
     
     
         4 . The article of footwear of  claim 1 , wherein the plurality of distinctly shaped cavities includes at least 50 distinctly shaped cavities, the plurality of distinctly shaped protrusions includes at least 50 distinctly shaped protrusions, and the plurality of distinctly shaped plastic fragments includes at least 50 distinctly shaped plastic fragments. 
     
     
         5 . The article of footwear of  claim 1 , wherein the sole structure includes recycled plastic material. 
     
     
         6 . The article of footwear of  claim 5 , wherein the sole structure is fabricated entirely from the recycled plastic material. 
     
     
         7 . The article of footwear of  claim 5 , wherein the recycled plastic material includes scrap and/or waste material comprising thermoplastic elastomer (TPE) plastic and/or ethylene-vinyl acetate (EVA) copolymer plastic. 
     
     
         8 . The article of footwear of  claim 5 , wherein the recycled plastic material includes a butadiene rubber. 
     
     
         9 . The article of footwear of  claim 5 , wherein the sole structure is fabricated from a mixture of the recycled plastic material and virgin polymer material. 
     
     
         10 . The article of footwear of  claim 9 , wherein the recycled plastic material includes scrap and/or waste ethylene-vinyl acetate (EVA), and wherein the virgin polymer material includes an EVA copolymer having 15-60 mole percent vinyl acetate. 
     
     
         11 . The article of footwear of  claim 9 , wherein the sole structure includes at least 40 parts of the recycled plastic material per 100 parts of the virgin polymer material. 
     
     
         12 . The article of footwear of  claim 9 , wherein the sole structure includes a chemical crosslinking agent linking a polymer chain of the recycled plastic material to a polymer chain of the virgin polymer material. 
     
     
         13 . The article of footwear of  claim 1 , wherein the sole structure is fabricated from a mixture of a recycled plastic material and a polyurethane (PU) base material. 
     
     
         14 . The article of footwear of  claim 1 , wherein the sole structure is fabricated from a mixture of a recycled plastic material and a virgin synthetic rubber material. 
     
     
         15 . The article of footwear of  claim 1 , wherein the sole structure, including the distinctly shaped cavities, the distinctly shaped protrusions, and the distinctly shaped plastic fragments, is integrally formed as a single-piece structure. 
     
     
         16 . The article of footwear of  claim 1 , wherein the plurality of distinctly shaped plastic fragments includes multiple distinctly shaped, sized, and colored plastic fragments. 
     
     
         17 . The article of footwear of  claim 1 , wherein the plurality of distinctly shaped cavities includes multiple distinctly shaped and sized cavities with irregular geometries. 
     
     
         18 . The article of footwear of  claim 1 , wherein the plurality of distinctly shaped protrusions includes multiple distinctly shaped and sized protrusions with irregular geometries.