Method for manufacturing a midsole formed from two preforms

Abstract

A method of manufacturing a midsole for an article of footwear includes placing first and second preforms in a first mold, closing and heating the first mold to produce a midsole preform with a peripheral preform flange, removing the midsole preform from the first mold and allowing it to further expand and cool, placing the midsole preform in a second mold, with a volume of a midsole recess of the second mold being less than a volume of the midsole preform, and a volume of a peripheral recess of the second mold being less than a volume of the peripheral preform flange, closing the second mold thereby compressing the midsole preform and the peripheral preform flange, and heating the second mold to form a midsole with a peripheral flange, allowing the second mold to cool, opening the second mold, and cutting away a peripheral flange of the midsole.

What is claimed is: 
     
         1 . A method of manufacturing a molded foam article for a midsole of an article of footwear, the method comprising:
 filling a mold by placing a first preform having a first volume in a recess in a mold, the mold having a mold recess and a peripheral overflow chamber, wherein the mold recess includes a forefoot mold region, a midfoot mold region, a heel mold region, and a peripheral edge extending continuously along the medial and lateral sides of the mold recess, connecting the forefoot mold region, the midfoot mold region, and the heel mold region, and wherein the peripheral overflow chamber extends continuously around the peripheral edge of the mold recess;   closing the filled mold;   molding the first preform by heating the first preform in the closed mold for a period of time and at a temperature such that the first preform expands into and fills the peripheral overflow chamber, forming a molded foam article having a first portion and a peripheral flange portion;   allowing the molded foam article to cool; and   removing the cooled molded foam article from the mold recess.   
     
     
         2 . The method of  claim 1 , wherein a depth and width of the peripheral overflow chamber are uniform around the peripheral edge of the mold recess, and the depth of the peripheral overflow chamber is uniform across its entire width extending out from the peripheral edge of the mold recess. 
     
     
         3 . The method of  claim 1 , wherein a volume of the mold recess is less than the first volume of the first preform. 
     
     
         4 . The method of  claim 1 , wherein the depth of the peripheral overflow chamber is less than a depth of the mold recess. 
     
     
         5 . The method of  claim 1 , wherein the mold is a two-piece mold including a first mold piece with a first mold recess and a first peripheral overflow recess, and a second mold piece with a second mold recess and a second peripheral overflow recess, the first and second mold recesses cooperating to define the mold recess, the first and second peripheral overflow recesses cooperating to define the peripheral overflow recess, and wherein closing the filled mold comprises aligning the first and second mold recesses and bringing the first and second mold pieces into contact with one another. 
     
     
         6 . The method of  claim 1 , wherein the first preform comprises an ethylene-vinyl acetate foam. 
     
     
         7 . The method of  claim 1 , wherein the step of filling the mold further comprises placing the first preform in contact with at least one second preform in the mold recess, the at least one second preform having a second volume. 
     
     
         8 . The method of  claim 7 , wherein the volume of the mold recess is less than the total of the first volume of the first preform and the second volume of the at least one second preform. 
     
     
         9 . The method of  claim 7 , wherein the first preform has a first thickness and the at least one second preform has a second thickness, and the second thickness is different from the first thickness. 
     
     
         10 . The method of  claim 7 , wherein the first preform comprises a first polymeric material, and the at least one second preform comprises a second polymeric material, and the second polymeric material is different from the first polymeric material. 
     
     
         11 . The method of  claim 7 , wherein the first preform has a first color, density or hardness and the at least one second preform has a second color, density or hardness, and the second color, density or hardness different from the first color, density or hardness. 
     
     
         12 . A molded foam article for a midsole of an article of footwear manufactured according to the method of  claim 1 . 
     
     
         13 . A molded foam article for a midsole of an article of footwear, comprising:
 a first portion comprising a first molded foam, the first portion including a forefoot region, a midfoot region, and a heel region; and   a peripheral flange portion comprising the first molded foam, the peripheral flange portion forming medial and lateral edges of the molded foam article and extending continuously around an entire periphery of the first portion.   
     
     
         14 . The molded foam article of  claim 13 , wherein a width and a thickness of the peripheral flange portion are uniform around the entire periphery of the first portion, and a thickness of the peripheral flange region is uniform across its entire width. 
     
     
         15 . The molded foam article of  claim 13 , wherein a thickness of the peripheral flange portion is less than a thickness of the first portion. 
     
     
         16 . The molded foam article of  claim 13 , wherein the first molded foam comprises an ethylene-vinyl acetate foam. 
     
     
         17 . The molded foam article of  claim 13 , wherein the molded foam article further comprises a second portion comprising a second molded foam, and wherein the peripheral flange portion comprises the second molded foam. 
     
     
         18 . The molded foam article of  claim 13 , wherein the first portion has a first thickness and the second portion has a second thickness different than the first thickness. 
     
     
         19 . The molded foam article of  claim 13 , wherein the first molded foam comprises a first polymeric material, and the second molded foam comprises a second polymeric material different than the first polymeric material. 
     
     
         20 . The molded foam article of  claim 13 , wherein the first molded foam has a first color, density, or hardness; the second molded foam has a second color, density, or hardness; and the second color, density or hardness is different from the first color, density or hardness.