Rheological Investigations of Water-based and Solvent-based Lacquer Varieties and Their Significance in Leather Coating Characteristics

Leather finishing plays a crucial role in determining the final product's appearance, durability, and performance. Traditionally, solvent-based lacquers have been used as topcoats, offering excellent protection but raising environmental concerns. The development of water-based lacquers presents a promising alternative, significantly reducing solvent emissions. This study explores five different lacquer types for leather finishing. This study investigates the impact of rheological properties on the performance of water-based and solvent-based lacquers for leather coatings. Lacquer rheology was evaluated at a fixed temperature using oscillatory and steady shear rheometry, along with frequency sweep tests. Evaluations of shelf-life, emulsion stability (in demineralized and hard water), wet/dry rub resistance, gloss, and film peeling assessed the lacquers' performance on leather. We found that rheological properties influence stability, adhesion, color fastness, and gloss. Solvent-based lacquers exhibited superior gloss, and high resistance to rub tests enhancing the aesthetic qualities of the final finish. These findings highlight the importance of rheology in selecting lacquers for leather coatings, offering a path towards improved durability, aesthetics, and broader applicability.