An environmentally friendly membrane 🌲


GRANTEX® is Graninge’s proprietary water-repellent membrane that is free from PFAS and other environmentally harmful substances. The membrane is made of polyester and breathes, wicks away moisture, and is water-repellent thanks to a physico-chemical process that simply pushes water molecules towards the outside of the material.


More about how GRANTEX® works:

The ability to breathe and transport moisture away arises through a unique physico-chemical process. The membrane itself is fundamentally composed of hydrogen, oxygen, and carbon, forming long molecular chains where the differences between positive and negative charges are minimal.

The water molecule, in turn, has a pole (on oxygen) with a negative charge. When the water molecule comes into contact with the membrane, it is drawn to the carbon molecules on the positively charged side, just as a magnet attracts iron. However, it does not stick in the same way as with a magnet; instead, it continues to migrate to the next molecule, and the water molecule immediately leaves the membrane on the other side.

The fact that the individual water molecule always follows the same direction is due to the inside of the membrane, i.e., inside the shoe, being warmer and more humid than on the outside. Since all systems will always strive to compensate for a pressure difference, the water molecule will inexorably be “pushed” towards the only possible direction, towards the outside. This also applies if the membrane is wet on the outside and reaches 100% humidity since the temperature inside will always be higher than on the outside.