Resilin material footwear and fabrication methods

Abstract

A method for making an article of footwear includes placing a purified recombinant resilin composition in a mold with a cross-linking solution, incubating the recombinant resilin composition in the cross-linking solution to generate a solid resilin material, fabricating a cushioning element of the article of footwear including at least a portion of the solid resilin material, and assembling the cushioning element insole with at least an upper of the article of footwear.

What is claimed: 
     
         1 . A method for making an article of footwear, comprising:
 placing a purified recombinant resilin composition in a mold with a cross-linking solution;   incubating the recombinant resilin composition in the cross-linking solution to generate a solid resilin material;   fabricating a midsole including at least a portion of the solid resilin material; and   assembling the midsole with an upper.   
     
     
         2 . The method for making the article of footwear of  claim 1 , further comprising:
 prior to fabricating the midsole, subjecting the solid resilin material to a solvent exchange process to substantially remove the cross-linking solution and configure the solid resilin material as a solid resilin material comprising a cross-linked recombinant resilin and a polar nonaqueous solvent.   
     
     
         3 . The method for making an article of footwear of  claim 2 , wherein the polar nonaqueous solvent is glycerol. 
     
     
         4 . The method for making an article of footwear of  claim 1 , wherein:
 the mold defines a shape of the midsole; and   fabricating the midsole includes removing the solid resilin material from the mold such that the entire midsole is of the solid resilin material.   
     
     
         5 . The method for making an article of footwear of  claim 4 , wherein the shape of the midsole defined by the mold is configured to compensate for subsequent shrinking of the solid resilin material by between about 20% and about 40%. 
     
     
         6 . The method for making an article of footwear of  claim 4 , wherein:
 the shape of the midsole defined by the mold includes at least one integral ground-contacting feature; and   the method does not include affixing an outsole material over the ground-contacting feature.   
     
     
         7 . The method for making an article of footwear of  claim 1 , wherein the incubation is carried out at a temperature of at least 60° C. for at least 15 minutes, at least 30 minutes, at least 45 minutes, at least 60 minutes, at least 90 minutes, or at least 2 hours. 
     
     
         8 . The method for making an article of footwear of  claim 1 , wherein the purified recombinant resilin material is a solution that further includes a foaming agent. 
     
     
         9 . The method for making an article of footwear of  claim 8 , wherein the foaming agent includes a mixture of ammonium persulfate and xanthan gum. 
     
     
         10 . The method for making an article of footwear of  claim 8 , wherein the purified recombinant resilin solution further includes fumed silica and sodium bicarbonate. 
     
     
         11 . The method for making an article of footwear of  claim 8 , wherein the purified recombinant resilin solution is vortexed and heated to promote development of air bubbles therein prior to being placed in the mold. 
     
     
         12 . The method for making an article of footwear of  claim 11 , wherein incubating the recombinant resilin composition in the cross-linking solution to generate a solid resilin material causes the air bubbles to form open cells within a matrix of the solid resilin material. 
     
     
         13 . The method for making an article of footwear of  claim 1 , further including fabricating an insole from a remaining portion of the solid resilin material. 
     
     
         14 . The method for making an article of footwear of  claim 13 , further including placing the insole within an interior of the upper and over a portion of the midsole. 
     
     
         15 . A method for making an article of footwear, comprising:
 placing a purified recombinant resilin composition in a mold with a cross-linking solution;   incubating the recombinant resilin composition in the cross-linking solution to generate a solid resilin material;   fabricating an insole including at least a portion of the solid resilin material; and   assembling the insole within an upper and over a portion of a midsole of the article of footwear.   
     
     
         16 . The method for making the article of footwear of  claim 15 , further comprising:
 prior to fabricating the insole, subjecting the solid resilin material to a solvent exchange process to substantially remove the cross-linking solution and configure the solid resilin material as a solid resilin material comprising a cross-linked recombinant resilin and a polar nonaqueous solvent.   
     
     
         17 . The method for making an article of footwear of  claim 15 , wherein the purified recombinant resilin material is a solution that further includes a foaming agent. 
     
     
         18 . The method for making an article of footwear of  claim 15 , wherein fabricating the insole further includes applying a material layer over the portion of the solid resilin material. 
     
     
         19 . The method for making an article of footwear of  claim 15 , wherein fabricating the insole includes cutting a portion of a sheet of the solid resilin material into a desired shape of the insole. 
     
     
         20 . A method for making an article of footwear, comprising:
 placing a purified recombinant resilin composition in a mold with a cross-linking solution;   incubating the recombinant resilin composition in the cross-linking solution to generate a solid resilin material;   fabricating a cushioning element of the article of footwear including at least a portion of the solid resilin material; and   assembling the cushioning element insole with at least an upper of the article of footwear.