PORTEFEUILLE

Being outside, even in the rain, is fun. More and more people want to experience nature as closely as possible. Proper equipment and clothing is fundamental for enjoyable outdoor sports. One large part is functional (i.e. waterproof and breathable) membranes, applied in rain jackets, tents and shoes. Nowadays functional clothing is made from laminates. A 2D membrane is produced, a glue is added and the membrane is laminated to a woven fabric. Outdoor brands buy the rolled laminate, cut it according to their design and have it tailored into clothing. Finally, the seams are covered with a waterproof but non-breathable tape. The seam taping accounts for about 40% of the assembly costs, causes defects to about 10% of the produced clothing and leads to about 12% loss in breathable area. We propose a novel approach to omit the taping.
Instead of producing a flat area of membrane, which is forced into a 3D shape by tailoring, we apply a liquid membrane precursor and directly form a 3D membrane. Our membrane process works with hard template particles, which are mixed into a polymer-solution. This precursor solution is applied on a substrate, the solvent is removed and the template particles are removed. A fully porous polymer membrane is obtained. A natural fatty acid, introduced into the pores as a coating on the template particles, introduces waterproofing into the pores.
In this project we investigated the application of the liquid precursor on a 3D substrate. The project will be continued to generate the first 3D membrane in clothing. The successful application reduces waste, cost in the assembly and greatly increases the wearers comfort.

This project covered the exploration of 3D membranes for outdoor clothing applications. The breakthrough invention will be the assembly of functional 3D membranes. A jacket, shoes or gloves will be produced and the functional membrane would be added later in its complete shape. Multiple issues of the current assembly will be omitted and clothing without using neither a glue nor a DWR (dureable water repellent) will be possible. This increases the functionality and therefore allows more activity without getting wet.
Furthermore, the specific way of assembly might allow local design and creation in the stores of the clothing brands.

Industrial scaling was successfully achieved in the project. The first laminates at full scaled width are being tested in the lab and in test collections. Along the scaling and testing it was established, that spraying membranes on the 3D fabric is the most promising option. The project will be continued with large partners in order to bring first 3D membranes to the customers.

M. Stucki, C. R. Kellenberger, M. Loepfe, W. J. Stark, J. Mater. Internal polymer pore functionalization through coated particle templating affords fluorine-free green functional textiles, Chem. A 2016, 4, 15197;
M. Stucki, W. J. Stark. Stabilization of 2D Water Films in Porous Triple Layer Membranes with a Hydrophilic Core: Cooling Textiles and Passive Evaporative Room Climate Control, Adv. Eng. Mater. 2017, n/a;
M. Stucki, M. Stöckli, W. J. Stark, Macromol. Thermoresponsive Microspheres as Smart Pore Plugs: Self Venting Clothing Membranes for Smart Outdoor Textiles, Mater. Eng. 2018.