Leather Science & Technology

1.7.1 SCIENCE, TECHNOLOGY & SERVICE

Non-zero Discharge Leather Processing

CLRI has developed a three step tanning methodology towards near zero discharge leather processing. Cow hides are dehaired using standard enzyme based dehairing method. The hides are treated with a–amylase 1% and water 100% for 3 h in a drum. Alternatively, the hides can be treated with 0.9% sodium hydroxide and 350% water in a drum; duration of treatment is one day. A pickle–basification free chrome tanning at pH 5.0 has also been developed with and without masking. The pH of the pelts is kept 5.0 using three different acids namely sulfuric, acetic and oxalic acid without sodium chloride. Speciation studies were carried out during the course of tanning in order to find the mechanistic pathway. A polymeric matrix based on naphthalene sulfonic acid has been prepared using polycarboxylic acid without employing formaldehyde. The product enables pickleless tanning thereby reducing the pollution load in terms of TDS and chlorides. The product not only enables higher exhaustion of chromium but also provides fuller leathers. It is now feasible to avoid Do-Undo process logic and produce Initiatives in polymer technology including synthesis of liquid crystalline polyether urethanes, sulfide copolymers, atom transfer radical polymerization technique for the synthesis of block copolymers.

Leather Processing Technology

CLRI has developed a database on TDS contribution from their commercial post tanning auxiliaries based on which processes for the production of cow softy upper leather and sheep nappa garment leathers with reduced TDS emission have been standardized.

Presence of Cr (VI) in tannery effluent has been a cause of concern since long. CLRI, an eco-conscious establishment, is making efforts to ensure production of Cr(VI)-free leathers, by avoiding formation of hexavalent chromium in leathers. A process technology for the production of Cr-free sheep gloving leather has been standardized and suitable post-tanning methods have been developed.

Moreover, CLRI has devised innovative strategies to produce low priced garments ranging from 20-35 US$. The production of such garments will earn India, a share in global middle market segment.

Leather Product Technology

CLRI has developed material and productivity optimization system and field tested it in a commercial shoe unit. Savings of around 10% in material consumption has been demonstrated resulting in 33% higher production.

CLRI has experimented with newer materials in shoe construction. Testing of various parameters has been completed. Wearer trials have been undertaken to assess comfort wear.

Alternatives to leather have been explored due to inelastic supply and unavailability of leather, increasing material requirement for meeting global demand, cost factor and specialized regional craftsmanship. These alternative materials have been assessed for their compatibility to leather in physical properties, workability, changes in design and construction methods. Based on the need for alternative materials and change in production methodologies, new products were developed using rigid materials such as bamboo, mats for flat and molded products; soft materials like jute and other woven and non-woven materials for bags and garments. Designing of innovative products for aesthetic appeal and cost effectiveness has been initiated using unconventional upgradation techniques. Exclusive and exotic products for home furnishing applications have opened up a new avenue for parchment like material made out of chrome shavings. Many workshops, entrepreneurship training programmes were conducted at different places to disseminate information to the industry on these innovative product ranges. Combination of leather with jute, silk, bamboo and wool has led to innovations in products. Determination of softness (leather), insulation property, productivity enhancement for leather products were studied. Other initiatives include development of low priced garments, development of materials for upholstery, glove making, bullet proof and protective garments.

Specialized Expert Services

Chemical pollution in leather sector predominantly due to the various processing chemicals used in the tanneries is a major concern. Some of the chemicals which have been banned include certain aryl amines, PCP, Cr (VI), formaldehyde, trace metals viz. Ni, Cd, Hg, As, Sn, phthalates, chlorinated phenols, polychlorinated short chain alkanes and alkyl tins. Taking into consideration the needs of the industry CLRI established a Centre for testing eco sensitivity of chemicals used in leather sector. The Centre offers world class testing services for testing toxicity of chemicals by tracking of PCP, tetrachlorophenols, trichlorophenols, and dichlorophenols.

Leather biotechnology

Leather industry generates enormous amounts of solid as well as liquid wastes causing ground and water pollution. Dehairing of skins and hides is one of the major sources of pollution. Enzymatic method of dehairing as an alternative to chemical method is gaining worldwide attention. A fungal strain isolated at secreting high levels of alkaline protease in short fermentation cycles was evaluated at CLRI. The dehairing of skins and hides in the absence of sulfide using NCL enzymes has been demonstrated in commercial tanneries. Attempts for transferring the technology are in progress.

Newer sources of proteases and lipases with properties suitable for application under field trials for their application in leather manufacture have been screened. Two proteases have been selected as lead enzymes for further scaling up and large-scale evaluation trials.

1.7.2 HUMAN RESOURCE DEVELOPMENT

  • 23 B.Tech. and 7 M.Tech. students have been trained. Courses have been designed for industry to meet the core competence of the personnel.
  • AFPA/AFPIC programmers have been conducted.
  • Specialized programmers for executives have been designed.
  • International training programmers include leather and leather products training for trainees from Ethiopia, Syria.