Biobased and isocyanate-free
Polyurethane (PU) is a versatile family of polymers that has many applications, including in coatings for the automotive industry, in cushions, mattresses and furniture upholstery, in insulation boards and foams for construction. The disadvantage of PU is that it is made from fossil raw materials and contains diisocyanate. The Flemish-Dutch Interreg project BioNIPU has managed to change that, by developing bio-based and non-isocyanate polyurethane (NIPU) for applications in the textile and synthetic rubber (elastomer) industry. The results were presented during a final meeting at Centexbel in Zwijnaarde (near Ghent).
Conventional PU is made from fossil raw materials (petroleum), while the trend is bio-based. For example, the textile sector wants to make at least 2030% of its products from biomaterials by 20. In addition, the European Commission is preparing new regulations (REACH) that will restrict the use of diisocyanates, a building block for PU, in the EU. The development of NIPUs that are biobased in origin is therefore an important step forward towards a more sustainable and healthier organic society.
Brand new
Biopolymers for textile coatings and elastomers such as PU are already available in small quantities. They are currently available for a limited number of applications and are only on average 50% bio-based. Moreover, there is hardly any research into the application of NIPU in coatings and elastomers. “The BioNIPU project concerns brand new applications,” says David De Smet of Centexbel.
The purpose of the BioNIPU project is to develop versatile and complete bio-based building blocks for these applications. Only renewable bio-raw materials are used for production, such as residual flows from sugar refining and biodiesel production, and natural oils and fats. The result after three years of research: 95% bio-based NIPUs synthesized via a mild route. For elastomers these can be used directly, for coating applications they only need to be dispersed in water.
Collaboration
To develop the technology from lab scale to industrial production, the BioNIPU project consortium included both knowledge institutions (University of Maastricht, Thomas More University of Applied Sciences, research Institute Centexbel) as the industry represented (PU producer LUC and coating manufacturer Steel).
Maastricht University has extensive expertise in the synthesis of biobased materials and developed bioNIPU on a lab scale. The synthesis was explained by researcher Enzo Pichon during the final meeting. In this case it concerns transurethanization, where the properties can be easily controlled by adjusting the process conditions.
The developed bioNIPU was applied by Centexbel on a small scale, where the processability and mechanical properties were also evaluated. This showed, among other things, that textile coatings with bioNIPU achieved good performance in terms of properties such as light and color fastness, washing resistance and waterproofness. The production of elastomers with bioNIPU has not yet reached that stage and still requires some research, for which a follow-up project may be started.
Optimize
Thomas More University of Applied Sciences repeated the lab procedures of Maastricht University to determine whether they could be optimized and then scaled up production from a few grams to a few ounces and then a few kilograms. Ward Ceunen from Thomas More, Campus Geel spoke about this during the final event. It led to samples with which the industrial partners in the consortium could carry out application tests.
The resulting samples were evaluated for industrial application by Stahl and LUC (Limburgse Urethane Chemie). “Thanks to our participation in BioNIPU, we were able to discover a completely new route for the synthesis of polyurethanes,” says Julien Verjans from LUC, a company specialized in customization in the field of synthetic rubbers. “In anticipation of the changing REACH regulations, it is important for us to take the first steps beyond life with diisocyanates. That was initially a challenge for us, but we have made significant progress.”
Paul Rouster from Stahl Holding, a company specialized in coatings and chemicals, points out the evolution of the chemical industry: “At the beginning of the last century, all our products contained solvents, but this has changed since the turn of the century. Now sustainability is one of the most important motivations for us to participate in this project. The BioNIPU chemistry enables us to operate greener and safer than ever. It's the future. We therefore expect that our LCAs with bioNIPU will be significantly lower.”
Source: Agro&Chemistry
