Pickling of sheepskin by benzene sulphonic acid with low-salt content to enhance shrinkage and mechanical properties

Abstract

This study aims to investigate the effectiveness of a novel ecofriendly pickling method using benzene sulphonic acid with reduced salt content to improve the mechanical properties of sheepskin leather while minimizing environmental impact. Sheepskins are treated using five different ratios of benzene sulphonic acid (C6H6O3S)/ sodium chloride (NaCl), while one sample was pickled using the conventional NaCl/sulphuric acid method. The remaining ingredients, formic acid and water, are kept constant. Among the treated samples, S1 treated with 5% of C6H6O3S with 4% NaCl exhibits the highest tensile strength (80.83 N/mm2), elongation at break (45.7%), tear strength (60 N/mm), and shrinkage resistance temperature (107 oC). On the contrary, the sample treated with 4% C6H6O3S and 3% NaCl shows the lowest mechanical and shrinkage properties. Statistical analysis confirms significant differences among the pickling treatments. The findings demonstrate that the proposed novel pickling of benzene sulphonic acid with low-salt content has the potential to enhance the mechanical properties of sheepskins, reduce environmental pollution, and be affordable cost since sulphonic benzene acid can replace the sulphuric acid application, which is used in the conventional process.