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.

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
  • The 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

Commercialization Status/ Techno - Economics:

  • Status of commercialization : This technology has been already commercialized
  • Licensed to one client
  • Major Raw Materials to be utlilized: Melamine, Organic acid, Basic Chromium Sulphate, Glyoxal
  • Validation level: 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.
  • Handholding support: Training, Demonstration, Technology Document, Trouble Shooting, Technology Implementation
  • Techno-Economics :
    • Optimum investment- for syntan manufacturers, the equipment available can beused for the preparation of this syntan also; Approximate payback period/ ROI - Cost of the syntan will be on par with the commercial chrome syntans

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

Commercialization Status/ Techno - Economics:

  • Status of commercialization : This technology is ready for commercialization
  • Major Raw Materials to be utlilized: Black liquor and acid
  • Validation level: Lab and Pilot scale trails were carried out
  • Handholding support: Training, Demonstration, Technology Document, Trouble Shooting, Technology Implementation
  • Techno-Economics :
    • Approximate payback period / ROI is 12 Months

Protein-Based Synthetic Tanning Agent

Technology Outline

  • Safe and environmentalfriendly separation of collagen hydrolysate from chrome shaving waste by alkali treatment.
  • Modification of collagen hydrolysate with natural polymer as retanning agent through simple polymerisation.
  • Developed syntan will be utilised as a retanning agent (syntan)during the post tanning process.
  • Crust leather made out of developed syntan showed good tight grain and better fullness.

Salient Features/ Highlights/ Advantages

  • Better utilisation of leather industry solid waste byintegration ofproteinous waste and polysaccharides.
  • Replacement for phenol and formaldehyde type syntan.
  • Better compatible with conventional post tanning chemicals like syntans, vegetable tannins and fatliquors.
  • Good quality leathers can be produced by using this bio-polymeric syntan as an alternative to commercial toxic syntan in leather wet end processing.
  • 50% reduction in the TS load.

Commercialization Status/ Techno - Economics:

  • Status of commercialization : This technology is ready for commercialization
  • Validation level: This technology has been up scaled to 5kg production scale at the pilot plant facility of CSIR-CLRI.
  • Handholding support: Training, Demonstration, Technology Document, Trouble Shooting, Technology Implementation

Utilization of Chrome shaving waste as a reducing agent in BCS manufacture

Technology Outline

  • Globally, around 0.8 million tons of chrome shaving wastes are generated annually, leading to the accumulation of solid waste in huge quantum.
  • Presence of chromium in the protein-based waste hinders its usage for other applications.
  • Incineration and landfills lead to the leaching of chromium into the environment.
  • Need of the hour "Technology for efficient recycling and reuse of solid waste".
  • Accordingly, a technology for sustainable usage of chrome shaving waste as a reducing agent in BCS manufacture has been developed.

Salient Features/Highlights/ Advantages

  • Meets all the requirements of BCS as per BIS norms.
  • Better masking and imparts a pleasant blue color to tanned leather.
  • Better exhaustion during the tanning process and uniform distribution of chromium in the wet-blue leather.
  • Improved fullness due to the presence of hydrolyzed protein in the prepared BCS.
  • Economically feasible - Cost of product is equivalent to commercial BCS.
  • Complete utilization of chrome shavings as a reducing agent eliminates the solid-waste disposal problem and promotes the concept of circular economy.

Commercialization Status/ Techno - Economics

  • Status of commercialization : This technology is ready for commercialization
  • Validation level: This technology has been up scaled to 50kg production scale at the pilot plant facility of CSIR-CLRI.
  • Handholding support: Training, Demonstration, Technology Document, Trouble Shooting, Technology Implementation

For further information

Head, Knowledge Portfolio Management Department (KPMD)
CSIR-Central Leather Research Institute

Adyar, Chennai, Tamil Nadu, India - 600 020

+91 44 24437273 +91 44 24912150

subhendu@clri.res.in & clriinfo@clri.res.in

 
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