Avaliação do potencial do líquido da casca da castanha de caju (CNSL) como matéria-prima alternativa para a produção de tintas sustentáveis de base oleosa

Abstract

The growing demand for environmentally sustainable solutions has driven research into alternative raw materials in the paint industry. Cashew Nut Shell Liquid (CNSL) stands out as a promising agro-industrial by-product due to its composition rich in phenolic compounds and its physicochemical properties suitable for the formulation of oil-based paints. This study aimed to evaluate the potential of CNSL as an alternative raw material for the production of sustainable paints through the characterization of its chemical properties and the analysis of the performance of CNSL-based paint formulations. To achieve the proposed objectives, an applied research approach was adopted, employing both qualitative and quantitative methodologies. The study was supported by bibliographic review, laboratory experimentation, and a case study. Laboratory analyses were conducted on both crude and refined CNSL samples, assessing parameters such as density, specific gravity, viscosity, and acid value. Subsequently, paints were formulated using CNSL, and their properties—viscosity, density, and drying time—were analyzed and compared against industry benchmarks for coating materials. The results revealed that CNSL exhibits physicochemical characteristics compatible with the used resins in oil-based paint formulations, particularly when refined. The formulated paints demonstrated satisfactory technical performance in terms of viscosity and film formation, with values of 64KU and 76KU although with drying times of 123,3s and 143,3s, exceeding industrial standards. This suggests the need for compositional adjustments through the incorporation of drying agents. Nonetheless, CNSL presents a viable ecological alternative, capable of reducing dependency on petroleum derivatives and promoting the valorization of local agro-industrial waste. In light of these findings, it is recommended that further studies focus on improving CNSL-based formulations, including chemical modification processes and pilot-scale testing. Research initiatives that leverage natural resources can play a crucial role in strengthening the sustainability of the Mozambican coating industry.