Patent ID: 11873536
Assignee: BEKEN ITALIA S.R.L.
Field: Chemical engineering (Chemistry)
Classification: CPC C | IPC C

Claim 11:
12. The process according to claim 1, wherein the tanning step is carried out in a drum as chrome tanning according to the following steps:
addition in the bath derived from the step of preparation for tanning of a Cr3+ salt in an amount between 5 and 8% with respect to the weight of the hide, optionally mixed with sodium sulphate, between 0.5 and 0.8% with respect to the weight of the hide of a mixture of C4-C6 dicarboxylic acids containing between 10 and 30% by weight of succinic acid, between 40 and 60% by weight of glutaric acid and between 15 and 35% by weight of adipic acid, and between 0.1 and 0.3% with respect to the weight of the hide of an antibacterial component, allowing the system to react under stirring for at least 8 hours;
addition of formic acid in an amount between 0.3 and 0.5% with respect to the weight of the hide, allowing the system to react under stirring for at least 2 hours;
addition of an antibacterial agent in an amount between 0.1 and 0.2% with respect to the weight of the hide and of a basic chromium-stabilizing compound in an amount between 0.2 and 0.5% with respect to the weight of the hide, allowing the system to react under stirring for at least 4 hours and then unloading the drum from the solution contained therein;
one or more washes with cold water in a total amount of about one and a half times the weight of the hide, with possible additions of formic acid and antibacterial agent in amounts of up to 0.1% each with respect to the weight of the hide, for a total time of about 2 hours and a half, and finally unloading the drum and recovering the hides that are sent to the steps following the tanning.