Method of manufacturing midsole for article of footwear

Abstract

A method includes placing first and second mold members in contact; injecting a first material into a first recess in the first mold member to form a first portion of a midsole while the first mold member is maintained at a temperature below ambient; removing the first portion of the midsole from the first recess; placing a third mold member and an intermediate mold member in contact injecting a second material into a second recess to form a second portion of a midsole while the second mold member is maintained at a temperature below ambient; removing the intermediate mold member; positioning the first and second portions in the second recess; placing the third mold member and the fourth mold member in contact with one another; and subjecting the second material portion and the first portion in the second mold assembly to heat and pressure to form a midsole.

What is claimed is: 
     
         1 . A method of forming a midsole with a first mold assembly having a first mold member and a second mold member with a first recess formed in the first mold member, and a second mold assembly having a third mold member, an intermediate mold member, and a fourth mold member with a second recess formed in the third mold member, comprising the steps of:
 placing the first mold member and the second mold member in contact with one another;   injecting a first material into the first recess in the first mold member to form a first portion of a midsole while the first mold member is maintained at a temperature below an ambient temperature;   removing the first portion of the midsole from the first recess;   placing the third mold member and the intermediate mold member in contact with one another;   injecting a second material into the second recess in the second mold member to form a second portion of a midsole while the second mold member is maintained at a temperature below an ambient temperature;   removing the intermediate mold member from the third mold member;   positioning the second portion and the first portion of the midsole in contact with one another in the second recess in the third mold member of the second mold assembly;   placing the third mold member and the fourth mold member in contact with one another; and   subjecting the second portion and the first portion in the second mold assembly to heat and pressure to form a midsole.   
     
     
         2 . The method of forming a midsole of  claim 1 , wherein the first mold member includes at least one additional first recess, an additional first portion of a midsole being formed in each additional first recess; and
 wherein the third mold member includes at least one additional second recess, an additional midsole being formed in each additional second recess.   
     
     
         3 . The method of forming a midsole of  claim 1 , wherein the first portion comprises a heel portion of a midsole. 
     
     
         4 . The method of forming a midsole of  claim 1 , wherein the first portion comprises a forefoot and midfoot portion of a midsole. 
     
     
         5 . The method of forming a midsole of  claim 1 , wherein the first material has a first density and the second material has a second density that is different than the first density. 
     
     
         6 . The method of forming a midsole of  claim 1 , wherein the first material has a first hardness and the second material has a second hardness that is different than the first hardness. 
     
     
         7 . The method of forming a midsole of  claim 1 , wherein the first mold member of the first mold assembly includes a channel, the channel extending between the first recess and an exterior of the first mold member. 
     
     
         8 . The method of forming a midsole of  claim 7 , wherein the first material is injected into the first recess through the channel. 
     
     
         9 . The method of forming a midsole of  claim 1 , wherein the first material is EVA. 
     
     
         10 . The method of forming a midsole of  claim 1 , wherein the second material is EVA. 
     
     
         11 . The method of forming a midsole of  claim 1 , wherein the second material is a second portion of a midsole. 
     
     
         12 . The method of forming a midsole of  claim 11 , further comprising the step of forming the second portion of the midsole in a cold molding process.