Breathable sole structure for footwear

Abstract

The instant invention is a breathable sole structure for footwear. The footwear sole structure includes an insole, an outsole, and a functional membrane system. The insole has an area with a plurality of holes therethrough. The outsole has an area with a plurality of holes therethrough. The functional membrane system has a microporous hydrophilic membrane and a microporous hydrophobic membrane. The insole and the outsole are bonded to each other, so that the functional membrane system is sandwiched therebetween; and furthermore, the functional membrane system is juxtaposed to said areas.

1 . A breathable sole structure for footwear comprising: 
 an insole having an area with a plurality of holes transversing said insole;    an outsole having an area with a plurality of holes transversing said outsole;    a functional membrane system, comprising a microporous hydrophilic membrane and a microporous hydrophobic membrane;    said insole and said outsole being bonded together; and    said functional membrane system being sandwiched between said insole and outsole, said functional membrane system further being located between said areas.    
     
     
         2 . The breathable sole structure for footwear according to  claim 1 , wherein said functional membrane system being a single laminated bi-layer functional membrane system.  
     
     
         3 . The breathable sole structure for footwear according to  claim 1 , wherein said insole and said outsole being bonded to each other by a method selected from the group consisting of press-gluing method, and injection molding method.  
     
     
         4 . The breathable sole structure for footwear according to  claim 1 , wherein said outsole further comprising a tread.  
     
     
         5 . The breathable sole structure for footwear according to  claim 1 , wherein said microporous hydrophilic membrane has a thickness in the range of 250 μ to 1200 μ; an average pore size in the range of 0.1 μ to 1 μ; a Gurley of 45 seconds/10 cc; and a porosity in the range of 60% to 70%.  
     
     
         6 . The breathable sole structure for footwear according to  claim 5 , wherein said microporous hydrophilic membrane further having an absorption according to the thickness in the range of 20 mg/cm 2  to 60 mg/cm 2 ; a desorption of 100%/2 h; and a permeability to steam according to thickness in the range of 60 mg/cm 2 /8 h to 130 mg/cm 2 /8 h  
     
     
         7 . The breathable sole structure for footwear according to  claim 1 , wherein said microporous hydrophobic membrane having a porosity in the range of 30% to 60%; an average pore size in the range of 0.02 μ×0.08 μ to 0.2 μ×1.5 μ; a thickness in the range of 8 μ to 50 μ; and a Gurley in the range of 5 to 100 seconds/10 cc.  
     
     
         8 . The breathable sole structure for footwear according to  claim 7 , wherein said microporous hydrophobic membrane further having a tensile strength (machine direction) in the range of 15 kpsi to 19 kpsi; and a tensile strength (transverse direction) in the range of 1.2 kpsi to 2.2 kpsi.  
     
     
         9 . The breathable sole structure for footwear according to  claim 1 , wherein said microporous hydrophobic membrane having a porosity of 55%; an average pore size of 0.209 μ×0.054 μ; a thickness of 25 μ or less; and a Gurley of at least 9 seconds/10 cc.  
     
     
         10 . The breathable sole structure for footwear according to  claim 1 , wherein said microporous hydrophilic membrane comprising a polyolefin.  
     
     
         11 . The breathable sole structure for footwear according to  claim 10 , wherein said polyolefin being selected from the group consisting of a polyethylene, a polypropylene, and combination thereof.  
     
     
         12 . The breathable sole structure for footwear according to  claim 1 , wherein said microporous hydrophobic membrane comprising a polyolefin.  
     
     
         13 . The breathable sole structure for footwear according to  claim 12 , wherein said polyolefin being selected from the group consisting of a polyethylene, a polypropylene, and combinations thereof.