Mechanical-physical methods for paint removal of recycled bumpers for revalorization in the automotive industry

The automotive industry uses plastics in the manufacture of car components due to their benefits such as weight reduction, high friction resistance, energy absorption, and versatility in blending with other materials and in its processability. A wide variety of plastic are used in vehicles. Although up to 13 different types of polymers may be used in a single car model, the most common is Polypropylene (PP). Nowadays, mechanical recycling is the most common method for recycling plastic waste from end-of-life vehicles in the automotive industry. However, challenges arise from material heterogeneity, presence of paint or impurities which affect mechanical properties and quality of recycled materials. Various chemical and physical methods to remove these impurities but economic, technical and feasibility considerations influence the adoption of technology in the industry. The current paper focuses on mechanical-physical procedures for paint removal from recycled automotive thermoplastics, aiming to maintain the properties of the polymer matrix and overcome environmental, economic and complex barriers. The used methods have shown success in removing paint from PP surfaces, with the pressing machine method with the best efficiency at a 38 % reduction. Despite not achieving over 90 % paint removal, these procedures establish fundamental principles for effective industrial mechanical paint depainting.