Isocyanate-free polyurethane binders in adhesive and coating applications
10. February 2025
Coating systems based on regenerative raw materials are still a niche product. Based on existing research results (TRL ≤ 4-6) in the field of isocyanate-free polyurethanes (NIPU) from regenerative raw materials, this project aims to create conditions that will make bio-based polyhydroxyurethane binders (PHU) more competitive compared to conventional polyurethanes (PU).
The focus here is on binders for adhesives and coatings. In the project, the water-soluble and biobased cyclic carbonates developed previously in NIPUWOOD (FKZ 49MF210085) are used as hardeners (non-toxic replacement of isocyanate) to formulate isocyanate-free water-based binders for coating systems and adhesives in combination with newly developed amine-containing prepolymers. In the development work carried out to date, it has been shown that multifunctional water-soluble amines are necessary for this purpose, which have suitable average molar masses, degrees of branching and functional densities.
In the planned project, bio-based, aqueous amine-containing prepolymers will be developed that can be formulated in aqueous systems in combination with the previously developed cyclic carbonates, thus leading to wood coatings with high hardness and scratch resistance and adhesives with high adhesion for wood and wood (products). In addition to isocyanate-free polyurethanes, the newly developed amines can also be used directly in bio-based epoxy resins, polyureas or polyamides.