(Innovative Modified
Natural Tannins)

EU Tanning Industry in numbers

EU tanning industry turnover
0 billion
leather manufactured per year
0 million sqm
Italian market share
0 %
people employed
0 thousand

how leather is tanned today

Currently, over 85% of the leather produced worldwide is tanned with Cr(III) salts due to its low cost, versatility of use and high quality of finished products. However, Cr(III) can oxidise into toxic and carcinogenic Cr(VI), both in finished leather and in wastewater.

The remaining hides are tanned without chrome salts, using synthetic tannins and aldehydes, that confer to finished leathers inferior physical and mechanical characteristics compared to chrome tanned leathers.

Also in this case, there are some health and environmental issues due to the hazardous substances used or released during the making of the leather and its entire life cycle. Moreover, some of these substances are being classified as more harmful.

Although extremely eco-friendly, natural tannins are suitable for a reduced number of applications and generate high chemical load in wastewater in terms of Chemical Oxygen Demand (COD) and Biological Oxygen Demand (BOD), due to the presence of non-tanning Low Molecular Weight Substances (LMWS).

Chrome Tanning Process (CTP)

Good physical and mechanical properties

Heavy metals;
Risks of toxicity and carcinogenicity by Cr(VI).

Syntans / aldehyde Tanning Process (STP)

Chrome-free white leathers

Concern in raw materials;
New hazard classifications.

Natural tannins Tanning Process (NTP)


COD / BOD impact on waste waters by non-tanning substances

the project

main steps

The leather tanning processes using these CMNT will have lower chemical hazards, sustainable costs, reduced waste and improved circularity (recycle/re-use of waste) compared to the conventional processes from based on chrome, synthetic tannins, and aldehydes thanks to:

  • An innovative purification process will allow to separate Concentrated Purified Natural Tannins (CPNT) from non-tanning Substances, starting from most commonly used chestnut and quebracho extracts.
  • A chemical modification of CPNT according to green chemistry principles (bio-based chemicals, zero-waste) to produce the final tanning agent, our CMNT.
  • A new leather making process including these modified natural tannins in order to reach new properties and performances, while turning leather scraps into organic fertilisers.
  • A replication of the LIFE I’M TAN process in other tanneries around the EU, drawing up a business plan for the market introduction of new products / processes.
  • An analysis of the innovative process impact through Life Cycle Assessment (LCA), Life Cycle Cost (LCC), Social Life Cycle Assessment (sLCA), with Environmental Product Declaration (EPD), Product Environmental Footprint (PEF) and Ecolabel certification to demonstrate the sustainability of the production chain, from natural tannins extraction to leather production and wastewater treatment.


The results of the I’M-TAN project will be measured according to different parameters linked to circular economy and sustainability principles. This is what we aim to reach:

chrome salts
0 %
aldehydes and phenols
0 %
natural tannins required for tanning
0 %
recycling of tanning bath
0 %
water consumption
0 %
COD / BOD in wastewater
0 %
recovery of non-tanning LMWS for animal feed
0 %
Recycle of CMNT leathers and scraps
0 %

The partners

With the contribution of the LIFE programme of the European Union.

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