The “BioSchutz” initiative, carried out from 1 September 2021 to 31 August 2023, was funded under the German Federal Ministry of Education and Research through IGF project 21988 N. The research consortium comprised the Research Association for Pigments and Coatings and the Fraunhofer Institute for Production Engineering and Automation (IPA) in Stuttgart. The project’s goal was to develop a biodegradable, chitosan‑based release coating that could replace conventional petroleum‑derived protective films used during the transport of industrial goods.
The scientific work focused on formulating two model release coatings that differ in their additive systems. For application on polymer surfaces and paints, a wetting additive (Additive 3) and an adhesion promoter (Additive 1) were incorporated, whereas coatings intended for metal and glass substrates were produced without these additives. The formulations were evaluated against a range of chemicals following ISO 2812 Part 1, including ethanol (10 min exposure), diesel fuel (1 h), 5 % NaOH (1 h), motor oil (16 h), hydraulic oil (16 h) and deionised water (16 h). The coatings showed acceptable resistance to most solvents, with the highest degradation observed only after prolonged exposure to alkaline conditions.
Mechanical performance was assessed through hardness, impact resistance, tensile strength, elongation at break, adhesion to aluminium and water‑induced delamination. The model coating achieved a hardness of approximately 500 g, comparable to commercial water‑dilutable release coatings. Impact testing using a multi‑stone impactor yielded a uniform score of about 1 for all products, indicating good resistance to sharp‑edge damage. Drying times were longer for the model coating (≈ 30 min) than for commercial products (≈ 15 min), attributable to a higher solvent content. Tensile tests revealed a maximum strength of 0.5 MPa for the griwecolor formulation, 3 MPa for the Jäger coating, 7 MPa for the chitosan‑based film, 15 MPa for the Heroal foil and 20 MPa for the Hesse Lignal release film. Elongation at break varied widely: 850 % for griwecolor, 340 % for Jäger, 16 % for the chitosan film, 400 % for Heroal and 43 % for Hesse Lignal. Adhesion to aluminium was strongest for Heroal (≈ 3 N / 10 mm), moderate for griwecolor and Jäger (≈ 1.25 N / 10 mm), low for the chitosan film (≈ 0.6 N / 10 mm) and weakest for Hesse Lignal (≈ 0.2 N / 10 mm).
Water‑resistance tests conducted at 40 °C and 100 % relative humidity for seven days showed complete removal of the Hesse Lignal coating, significant structural changes for griwecolor and Jäger, and only minor blistering for the chitosan film. These results indicate that while the chitosan‑based coatings possess adequate mechanical robustness for many applications, further optimisation of adhesion and water stability is required for full industrial adoption.
The project concluded with a comprehensive final report, three peer‑reviewed publications, and the transfer of the developed formulations to industrial partners. The collaboration between the research association and Fraunhofer IPA facilitated the rapid translation of laboratory findings into prototypes that can be directly tested on industrial substrates, thereby advancing the use of renewable polymers in protective coatings.