Replacing windows with greener frames
Plastic materials are widely used for window applications. However, they are usually based on oil and fossil fuel-based products that one day may no longer be available. These synthetic polymers need to be replaced in part at least by a renewable and sustainable resource. This was the goal of the 'Extruded window profiles based on an environmentally friendly wood-polymer composite material' (EXTRUWIN) project, funded by the EU. The specific project objective was to develop a window profile made from a WPC for the European market. These novel profiles will have improved physical properties at lower production costs compared to existing products. In order to achieve its objective, the EXTRUWIN project set out to identify suitable raw materials and then formulate, compound and shape them into window profiles. These new profiles also required the development of appropriate bonding and coating techniques. Various WPC formulations based on thermoplastic matrices and blends were developed by the EXTRUWIN project. Compounds were then produced from the composites using a ring die press, a twin-screw extruder and a heating mixer. In the next stage, WPC profiles were extruded into various shapes and tested for their mechanical and physical properties. Unfortunately, it was not possible to extrude a window profile because of various technical challenges encountered by the project before completion. The experience gained from the EXTRUWIN project will prove invaluable for future projects in this field. In particular, the knowledge that not every WPC compound can be processed with existing equipment implies that tools will have to be developed for each compound formulation and every application.
