Multilayer insole

Abstract

Multilayer insoles made of several layers of polymeric materials and used for insertion into footwear, for example, for hygienic and orthopedic purposes. Multilayer insoles having increased manufacturability, absorption properties and low cost of environmentally friendly raw materials obtained from renewable sources.

What is claimed is: 
     
         1 . A multilayer insole comprising:
 a base configured to fit to an inside of a shoe sole;   a foam layer located above the base; and   a fabric layer located above the foam layer;   wherein the base comprises a rigid bio-based polyurethane;   wherein the foam layer comprises a foamed bio-based polyurethane; and   wherein the fabric layer comprises at least one of lyocell and bio-based polyamide.   
     
     
         2 . The multilayer insole of  claim 1 , further comprising a composite layer located between the base and the foam layer, wherein the composite layer comprises a bio-based thermoplastic polymer, and wherein the composite layer is configured to support an arch portion of a user's foot. 
     
     
         3 . The multilayer insole of  claim 2 , wherein the bio-based thermoplastic polymer comprises wood or cellulose fibers. 
     
     
         4 . The multilayer insole of  claim 1 , wherein the fabric layer comprises a mixture of at least one of lyocell and bio-based polyamide, and coal of plant origin. 
     
     
         5 . The multilayer insole of  claim 4 , wherein particles of coal of plant origin are integrated into fibers of the fabric layer. 
     
     
         6 . The multilayer insole of  claim 1 , wherein the base comprises at least one elastic insert made of a bio-based polymer. 
     
     
         7 . The multilayer insole of  claim 6 , wherein the bio-based polymer of the at least one elastic insert is selected from a group consisting of polyurea and a thermoplastic elastomer of copolymers of polyethylene and polypropylene. 
     
     
         8 . The multilayer insole of  claim 6 , wherein an inner volume of the at least one elastic insert is filled with gel. 
     
     
         9 . The multilayer insole of  claim 1 , wherein the foam layer is configured to cushion a user's foot 
     
     
         10 . The multilayer insole of  claim 1 , wherein the foamed bio-based polyurethane is a shape memory foam. 
     
     
         11 . The multilayer insole of  claim 1 , wherein the fabric layer has a hygienic and absorbent function. 
     
     
         12 . The multilayer insole of  claim 1 , wherein the bio-based polyurethane base is selected from a group consisting of bio-based polyurethanes Pearlbond ECO (also known as Lubrizol), Renuva manufactured by Dow Chemicals, JEFFADD manufactured by Huntsman, Recypol, Econykol manufactured by Mitsui Chemicals & SKC Polyurethanes Inc. 
     
     
         13 . The multilayer insole of  claim 1 , wherein the shape memory foam is Bio-Pur manufactured by Amerisleep. 
     
     
         14 . The multilayer insole of  claim 1 , wherein the lyocell is tencell fiber manufactured by Lenzing Gruppe or Everest. 
     
     
         15 . The multilayer insole of  claim 18 , wherein the thermoplastic polymer is selected from a group consisting of bio-based thermoplastic polyurethane Ellastolan, bio-based ethylene vinyl acetate SVT manufactured by Braschem, polystyrene thermoplastic elastomer MEGOL BIO manufactured by Trinseo and thermoplastic elastomers Terraprene manufactured by FKuR Polymers GmbH and Dryflex Green manufactured by Hexpol. 
     
     
         16 . A method of making a multilayer insole comprising the steps of:
 providing a base configured to fit to an inside of a shoe sole;   placing a foam layer above the base and adhering the foam layer to the base; and   placing a fabric layer above the foam layer and adhering the fabric layer to the foam layer;   wherein the base comprises a rigid bio-based polyurethane;   wherein the foam layer comprises a foamed bio-based polyurethane; and   wherein the fabric layer comprises at least one of lyocell and bio-based polyamide.   
     
     
         17 . The method of making a multilayer insole of  claim 16 , further comprising the step of placing a composite layer between the base and the foam layer and adhering the composite layer to the base and the foam layer, wherein the composite layer comprises a bio-based thermoplastic polymer, and wherein the composite layer is configured to support an arch portion of a user's foot. 
     
     
         18 . The method of making a multilayer insole of  claim 16 , further comprising the step of placing at least one elastic insert in the base, wherein the at least one elastic insert is made of a bio-based polymer. 
     
     
         19 . The method of making a multilayer insole of  claim 16 , further comprising the step of filling an inner volume of the at least one elastic insert with gel.