Binder for cork

Have you tried urea formaldehyde?

This is being used to make sheets from wood chips, it should work with cork as well.

Johan.

In the past, Unisoles and sheets of cork were made by mixing the cork granules with an aromatic moisture curing polyurethane, typically a polyether blend of diols and triols. The mix was then spread into a heated mold and cured, either by added moisture, added gylcerine or similar. One can vary the density, flexability and physical properties of the sheet, or Unisole, by varying the polymer, blend ratio, cure pressure (density) and so on. Millions of Unisole units have been made in the last 30 - 40 years. The polyurethane is typically a low cost commodity polyurethane.