Leather Chemicals

CLRI has over the years built up a strong base of a wide range of technologies. Conscious efforts are made by this Institute to secure appropriate Intellectual Property (IP) Rights like PATENT (in India and abroad) and COPYRIGHT in respect of the new developments.


Retanning Cum Lubricant Agent- Relub-17r

Technology Outline

Retanning and fatliquoring are two segments of post tanning that consume time as well as various chemicals for processing. To reduce the chemical load on final product (leather), a product designed by commingling the properties of a retanning agent and fatliquor using biodegradable raw materials.

Salient Features/ Highlights/ Advantages

Usage of this product reduces processing time and usage of number of chemicals alongside no harmful effects on handling and to environment

Business Case and Translation Status

Upscaled the product to 10 Kg level and consigned to three chemical houses for evaluation and simultaneous in-house leather trials are carried out. The product is ready for commercialization.

Retanning Agent Protan Khr

Technology Outline

About 50-70 kg of hair is produced from one ton of raw hides during`pretanning operations. The Protan KH is a polymeric syntan, containing protein hydrolysate of hair. The product is recommended for use in all type of leathers where fullness and tightness are required.

Salient Features/ Highlights/ Advantages

  • Protan KH is free of APED, AOX and does not contain free formaldehyde
  • Protan KH enhances dye uptake
  • As a syntan improves the roundness and grain tightness of leather

Business Case and Translation Status

Upscaled the product to lO Kg level and consigned to three chemical houses for evaluation and simultaneous in-house leather trials are carried out. The product is ready for commercialization.

Protein Based Retanning Agent Crostan Ea

Technology Outline

Crostan EA is soft polymeric retanning agent that has been prepared by polymerization using proteinous material sourced from one of the solid wastes of leather industry and monomer. It brings about excellent tightness and fullness. It improves the dye uptake. It is also used for manufacturing all types of leather where tightness and fullness are required.

Salient Features/ Highlights/ Advantages

It gives excellent exhaustion of dye, fullness and round handle. It also gives excellent light, heat and migration fastness. It improves belly filling. It provides better softness and uniform color to all types of leathers. It also gives better chrome exhaustion in chrome tanning process.

Business Case and Translation Status

The product has been prepared at pilot level of l00 kg and demonstrated to the commercial tannery. The product also been evaluated by Leather Chemical Manufacturers Association. The product is ready for commercialization.

Protein Based Retanning Agent Dermatan Rt

Technology Outline

Technology was developed as a part of XII Five Year Plan projects "Zero Emission Research Initiatives for Solid Wastes from Leather (ZERIS)". In conventional posttanning process, large numbers of re-tanning agents are employed to improve the fullness, roundness, grain tightness and light fastness of the leather. Most of the re-tanning agents used in the conventional post-tanning process are hard for biodegradation. In addition to that the presence of free formaldehyde is the major concern. Therefore, the development bio-degradable syntan devoid of formaldehyde is` emerging. Solid waste generated from the leather industry such as raw trimmings contain two important bio-polymer namely collagen and keratin. These biopolymers have been hydrolyzed into poly-peptide and further modified with additives. The modified poly-peptide is used as a syntan in leather processing.

Salient Features/ Highlights/ Advantages

  • Complete utilization of raw trimming without generating any secondary solid waste
  • Organic content of the product is more than 90% and easily biodegradable
  • Imparts fullness and roundness
  • Improved physical strength characteristics specifically grain crack resistance
  • Improved dye intensity
  • Excellent improvement in surface polishability
  • Completely free from harmful substances

Business Case and Translation Status

Pilot scale trial for preparation of syntan was carried out using 100 kgs of trimming. The performance of the prepared syntan was also observed to be good for making various types of leathers. The technology is patented and is ready for licensing.

Chrome-Melamine Syntan

Technology Outline

Leather chemicals manufacturers are facing stringent restriction on the use of toxic substances and their presence in final product Syntans are products of addition and condensation polymerization Significant drawbacks associated with condensation product is the use of formaldehyde as cross-linker, which is proven carcinogen The presence of free formaldehyde in leather and leather products, even at low ppm is becoming a huge cause of concern for leather manufactures Re-chroming is carried out to ensure uniform Cr203 content in the leathers procured from different sources Chrome-syntan (chromium and phenol or its derivatives-formaldehyde condensate product) is widely used for rechroming Use of formaldehyde condensate based mineral syntan in leather processing is not environmentally benign Melamine-formaldehyde condensate is used for preferential filling Combination of formaldehyde free melamine condensate and chromium melamine based syntans not available Keeping in mind the strictures on presence of free formaldehyde and the advantages that a melamine based product in association with chromium, could offer, this product- Chromium-Melamine Syntan (CrMS) has been developed.

Salient Features/Highlights/ Advantages

  • Zero formaldehyde
  • Eco-friendly with no possibility of Cr(VI)
  • Selective filling and grain tightening effect on loose area and belly region
  • Provides fine grain with soft handle
  • Increase in thickness without affecting area yield
  • Good dye levelling, excellent buffability with natural sheen
  • Produces uniform milling pattern
  • Overall quality enhancement and better cutting value

Business Case and Translation Status

Pilot scale trial for preparation of syntan was carried out using 100 kgs of trimming. The performance of the prepared syntan was also observed to be good for making various types of leathers. The technology, is paternea and the product is already commercialized.

Retanning Agent Nanotan Np

Technology Outline

Nanotan NP is a nanopolymeric retanning agent that brings about fine and smooth grain with excellent fullness. The leather treated with Nanotan NP if of round handle and improved grain tightness. The leather is not loaded and the softness is not impaired while using Nanotan NP. It enhances the fastness to light, heat and migration. It can also be used for finishing along with protein and resin binders. As a finishing agent, it provides excellent gloss and fine grain with smooth touch.

Salient Features/ Highlights/ Advantages

Nanotan NP provides the following properties to the leather when used in retanning, (i) Fine and smooth grain, (ii) Excellent fullness and round handle without loading, (iii) Better penetration and dispersion of other anionic auxillaries, (iv) Uniform dyeing, (v) Improvement in fastness to light, heat and migration, (vi) Low COD, VOC, Fogging and (vii) free from APED, AOX and does not contain free formaldehyde. It is suitable for the manufacture of all types of leathers, where fullness, smoothness and tightness need to be achieved without over loading the grain.

Business Case and Translation Status

India: Potential sales volume: 2 kilotons p.a (Assuming l 0% of volume) Value: Rs. 300 million p.a Likely profit: Rs. 228 million Global Potential sales volume: 18.3 kilotons p.a (Assuming l 0% of volume) Value: USS 39.2 million Likely profit: US$ 29.8 mil. (Rs. 2.1 billion) The product is readyfor commercialization

Lignin Based Retanning Agent

Technology Outline

  • Effluent from paper and pulp industry is predominantly contain large amounts of polyphenols like lignin and fragmented lignin.
  • Leather industry consumes huge amount of synthetic phenol-formaldehyde resin as a re-tanning agent to improve the homogeneity and organoleptic properties of leather.
  • SPresence of free formaldehyde in leather is a major concern because of its carcinogenicity. Hence, the development of phenolic re-tanning agent devoid of formaldehyde is emerging.
  • Waste liquor collected from paper and pulp industry has been chemically modified and used as re-tanning agent in leather manufacturing.

Salient Features/ Highlights/ Advantages

  • Utilization of paper and pulp industry waste as a re-tanning agent
  • Product is free from formaldehyde
  • Imparts excellent softy touch and wet feel to the leather
  • Smooth and fine grain
  • Compactable with all kind of syntans, vegetable tannins and fatliquors

Business Case and Translation Status

  • Product developed has been validated as re-tanning agent at
  • CLRI pilot tannery and also in a commercial tannery at Ranipet
  • The product is ready for commercialization

For further information

Head, Project Planning & Business Development
CSIR-Central Leather Research Institute

Adyar, Chennai, Tamil Nadu, India - 600 020

+91 44 24437191 +91 44 24912150

ppbd@clri.res.in & clriinfo@clri.res.in