Study of Waterborne Eco-Sustainable Paint with Plant, Shells and Cuttlefish Bone Powder Based Additives.

In paint production, there is increasing demand for eco-sustainable products made from natural or recycled materials. Paints must offer not only corrosion and abrasion resistance but also good aesthetic properties. This study investigates two bio-based fillers: one plant-derived and one animal-derived. The plant-based filler was Tagua, a seed from Phytelephas macrocarpa known as "vegetable ivory." The animal-derived fillers came from waste shells and cuttlebone, composed mainly of calcite and aragonite. These materials were micronized and used as alternatives to synthetic fillers in water-based acrylic paint. Four types of powders—Tagua, shells of Acanthocardia tuberculata and Mytilus galloprovincialis, and cuttlebone—were added at 3% wt. concentration to paint applied on carbon steel panels. A paint without filler served as the reference. The modified paints were evaluated for mechanical resistance and corrosion protection. Abrasion resistance was tested using a Scrub test, showing that cuttlebone powder provided the best performance. Aesthetic stability under artificial weathering was assessed via xenon light exposure, monitoring gloss and color changes. Corrosion resistance was tested using salt spray chamber exposure and electrochemical impedance spectroscopy in NaCl solution. Results highlighted that while Tagua powder improved abrasion resistance, it also increased water uptake, reducing corrosion protection. In contrast, cuttlebone fillers enhanced both abrasion and corrosion resistance. This study demonstrates the potential of using food and plant waste as functional fillers in sustainable coatings.