Enhanced chrome tanning process
31 January 2022
The invention relates to an electrochemical process of leather tanning. Conventionally, process of leather tanning require hours of treatment to allow olating agents to spontaneously diffuse through hide porosities. By the application of an electric field through the hide, required process time and exhaust bath volume are greatly reduced.
The invention provide with the possibility to employ different olating agents for hides tanning, not limited to Chromium (III) and metal salts (e.g. Fe (III), Zr (IV), Ti (IV) etc.) but also to organic as tannins. Time for tanning process, conventionally divided in three steps (pickling, tanning and basification), can be considerably reduced forcing the ionic migration through the hide when it is placed between two electrodes polarized with a potential difference. According to an embodiment of the invention, using a suitable separating membrane (anionic or cationic), pH of the tanning bath can be tuned avoiding the adding of other chemical agents in each of the process step. Overall, besides the reduction of process time, the inventions provide with a great reduction in tanning bath volume required for the process.
The principal advantages are:
- The electrochemical process significantly reduces required time to obtained tanned leather;
- employment of a very small bath volume to hide area ratio;
- possibility to use different olating agents other than chromium (III) salts.
Referente: Politecnico di Milano