Biobased Polyurethane Research Delivers Impressive Results!
Polyurethanes play a crucial role in textile applications, offering properties such as flexibility, durability, abrasion resistance, and water repellency. They are widely used in coatings, laminates, and functional finishes across apparel, upholstery, and technical textiles. However, their extensive use comes with environmental challenges. From production to end-of-life, conventional polyurethanes, often derived from fossil-based raw materials and formulated with organic solvents, contribute to greenhouse gas emissions, resource depletion, and VOC release. Disposal at the end of life typically involves incineration or landfill, further impacting the environment.
To address these concerns, bio-based polyurethanes have emerged as a sustainable alternative. By incorporating renewable raw materials, we can reduce dependency on fossil resources and lower the carbon footprint. Equally important is the shift from solvent based to waterborne polyurethane dispersions (PUDs), which significantly minimize VOC emissions and improve worker and environmental safety.
Water repellent polyurethanes
Centexbel is developing bio-based waterborne PUDs for advanced applications. Our water repellent polyurethanes are designed as fluorine-free alternatives for textile finishing, developed in framework of the PFAS-Free project and supporting the industry’s move away from harmful fluorochemicals.
Figure 1 compares the water repellency of the developed PUD with a PFAS-free commercial product before and after 25 washing cycles assessed through spray test (ISO 4920). Initially, both treatments achieved a spray rating of 5, indicating no surface wetting. However, after 15 wash cycles, the commercial product lost its water repellency, whereas the fabric treated with our developed PUD maintained a spray rating of 4, demonstrating superior durability and water repellency.
Figure 1: Spray rating of the polyester fabric treated with a commercial PFAS-free product and PUD developed at Centexbel. The spray rating is an indication of the water repellency of the fabric as the spray rating of 5 shows the highest surface water repellency of the fabric.
The PFAS-FREE project is part of the National Recovery and Resilience Plan and funded by EU.
Self-healing bio-based PU coating
In parallel, we are developing self-healing bio-based polyurethanes for building envelopes, extending material lifespan and reducing maintenance needs in the framework of SUBBIMATT project. Figure 2 shows the scanning electron microscopy image of the self-healing PU coated on polyester fabric after applying a scratch (a) and after healing of the scratch at 100° C for 24 hours (b).
Figure 2: Scanning electron microscopy image of the scratched self-healable PU coating before (a) and after (b) healing process at 100° C for 24 hours.
In both projects, we use bio-based and sustainable building blocks tailored to each application. Finally, we assess the end-of-life and recyclability of these products to ensure a truly circular approach.
SUBBIMATT is funded by the European Union under the Horizon Europe Programme, Grant Agreement number 101129911.
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