Debonding on demand primer for wood coatings based on solid-liquid hysteresis

Implementation of circular aspects into coated materials is ever more demanded. Therefore, it is crucial to remove the coating as one of the first steps. In the state of the art, this is achieved by means of mechanical, chemical, or thermal methods. All of them lead to destruction of the coating layer, which complicates its proper recycling or disposal, or even releases harmful dust, VOCs, or gases. In this work, a novel liquefiable primer system enables effective separation of a coating from its substrate in one piece. Chemically, the process of liquefication works via a thermally triggered hysteresis between a crosslinked, solid state and a monomeric, liquid state, which is achieved via covalent adaptable networks. Prominently, the liquid state is maintained for several hours, even after cooling to room temperature. The accompanying loss of adhesion allows for easy removal of the coating layer from the liquid primer. • Coating layers were removed from wooden substrates, using a liquefiable primer with solid-liquid hysteresis. • The primer promotes strong adhesion, while triggering at 130 °C for 10 min enables facile debonding. • After application of the trigger, separation of the coating and the substrate can be carried out at room temperature. • The debonding process is virtually independent of the coating’s properties.