The potential of near infrared (NIR) spectroscopy coupled to principal component analysis (PCA) for product and tanning process control of innovative leathers

The tanning industry faces significant challenges in quality control due to the complex transformations of leather, the anisotropic nature of the raw material, and the increasing adoption of innovative processes and materials in the tanning methods. In this study, it was possible to evaluate the applicability of a Non-Destructive Testing (NDT) technique such as near infrared (NIR) spectroscopy applied to the new generation of tanning products and processes as a potential technique for supporting product and process quality control activities. A microNIR sensor was employed to analyse intermediate leather samples, nano-functionalised finishing products, and tanning waters. By means of Principal Component Analysis (PCA), it was possible to differentiate tanned products with traditional processes and innovative methods. The same chemometric model was applied for process control when using nanostructured substances which helped to assess how effectively the nanostructured agents were incorporated into the final material. These results demonstrated how NIR spectroscopy coupled with chemometric models can provide real-time insights into traditional and innovative tanning processes, optimise resource consumption, and support sustainability in the leather industry.