Leather Processing

Disclosed herein is an integrated process of dehairing and fibre opening using significantly reduced amount of water and chemicals, optionally in the presence of enzymes. The process has enormous application in leather processing industry as an environment friendly option with a potential of reduction of generation of effluent to the extent of 50-75%. Further, the process also ensures significant time economy, thereby enhancing the productivity without sacrificing the final quality of leather.

Disclosed herein is a multifunctional smart leather exhibiting both electrical conductivity and magnetic field-response. It is prepared in a wide variety of colours without the use of synthetic or natural dyes or pigments by employing a layer-by-layer multicoating technique using magnetic and conductive substances. The leather has potential uses in the field of smart lifestyle products. It also finds application in the domains of electronics, sensors and allied sectors. The product is anticipated to have a multitude of applications in the leather products industry such as smart/interactive clothing, adhesive-free wall covering, sensors, conductive gloves/apparel, electromagnetic interference shielding, intelligent garments, magnetically controlled reed switches, and the like. Further, the process for the prepration of the said multi-coated smart leather finds application in leather processing industry to produce multifunctional specialty leather.

Disclosed herein is a transparent leather exhibiting transmittance in the range of 80 – 85%. The leather is produced by treating pretreated pickled skin with polyol-oil combination under controlled condition of pH and temperature. The invention finds application in leather processing industry for making high value leather in an eco-friendly manner. Further, the transparent leather of the invention finds application in product industry for making apparels and other lifestyle products of aesthetic value. Indian Patent application no. 202011023592

Disclosed herein is a bi-functional leather responsive to electrical conductivity and magnetic field with different range of colours simultaneously by a single coating technique without employing any synthetic or natural dyes or pigments. The processed leather of the invention can be used for smart product applications. The structural and morphological features of the resultant leathers were not altered significantly. Depending on the choice of chemicals, leathers with satisfactory electrical conductivity and magnetic behaviour with different colour shades can be obtained. Such leathers are suitable for manufacturing smart leather products, which have potential applications in smart/interactive clothing, adhesive-free wall covering, sensors, conductive gloves/apparels, electromagnetic interference shielding, intelligent garments, magnetic controlled reed switches etc. Indian Patent application no. 202011034409

Disclosed herein is an improved process of leather making using 10-100% w/w, of Aloe vera extract to obtain conditioned leather, which is subjected to conventional tanning or post tanning unit operation to obtain wet processed leather. The process utilizes aloe vera extract as a medium for leather processing and hence no additional water is required. This essentially ensures exhaustion of chemicals during tanning and post tanning process without adding water or any other medium. Thus, the process provides an efficient way to minimize the effluents generated by the conventional leather manufacture, thereby providing a sustainable solution for waste minimization in leather making. Indian Patent application no. 201911045023

Disclosed herein is a process for leather making using Artemisia pallens plant. Partially processed leather exhibiting surface pH in the range of 4.0-6.0 is treated with the said plant powder/extract under specified conditions and then processed conventionally to obtain antifungal fragrant leather. The leather of the invention finds applications in consumer product industry. The invention finds application in leather processing industry to produce fragrant leather with antifungal effect. Indian Patent application no. 202011002575

Disclosed herein is a process of post tanning with no discharge of any wastewater. The waste streams from the unit processes of post tanning are segregated and screened for removing gross solids. The waste streams are treated by electro-oxidation with or without UV treatment. The treated sectional streams are reused for appropriate unit process. The reuse can be carried out continuously to attain zero wastewater discharge. Indian Patent application no. 201711040533.

Disclosed herein is essentially a specific cyclic carbonate mediated process of treating hide/skin, optionally in the presence of terpene or derivatives thereof, and surfactant, to obtain dehaired hide/skin that can be stored upto 60 days. The unique advantage of the process is that it completely eliminates salt for preservation, lime/sulphide for dehairing. No water is required for rehydration of preserved hides/skins. The process finds potential application in leather processing industry for temporary preservation of hides/skins and hair removal in absence of water, thereby curtailing TDS and eliminating toxic sodium sulphide in effluent load. Indian Patent application no. is 2352DEL2015.

Disclosed herein is an improved process for enzyme based dehairing and fibre opening of skins and hides without employing water. The use of organic solvents with low dielectric constant in conjunction with commercially available enzymes enhances the efficiency of hair removal and fibre opening. The process does not employ the conventional chemicals such as lime and sodium sulphide. The solvent is recovered for recycling. The physical and chemical properties of the bioprocessed leathers match with conventionally processed leathers. This improved bioprocess based on organic solvents offers an alternative and efficient way for dehairing and fibre opening with complete elimination of water, lime and toxic sodium sulphide. Indian Patent application no. is 2729DEL2015.

Disclosed herein is a process for making retanned leather with dyeing effect using a lignin source. The process ensures lignin mediated single step retanning cum dyeing operation in leather making. The process finds enormous application in post tanning wet processing for leather making, whereby it is possible to have a range of shades in the wet processed leather without applying any conventional dyestuff. It also finds application in the economical utilization of the effluents generated by the lignin based processing industries, thereby providing an eco-benign solution for the disposal of the wastes generated by paper and pulp industry. Indian Patent application no. is 3120DEL2015.

Disclosed herein is a method for the preservation of hides and skins using supercritical carbon dioxide. The process involves establishing contact between hide/skin and supercritical carbondioxide to ensure that the hides/skin can be preserved for upto 90 days. The process completely eliminates use of salt in hide/skin preservation leading to no salinity burden of soak liquor effluent. Indian Patent application no. is 201611002827.

Disclosed herein is a process for leather making using plant material, which may be hydrolysable tannin/condensed tannin/natural dye bearing plant. It essentially relates to simultaneous solid-liquid extraction of active ingredients of plant materials as well as treatment of such extracts in leather processing. This process also offers better penetration/diffusion of tanning agents in the skin/hide/leather matrix. This process provides better extraction efficiency and better diffusion and exhaustion of extracts in leather. It is essentially an eco-friendly, non-toxic and non-hazardous process for leather making. Indian Patent application no. is 201611003057

Disclosed herein is a process to avoid the use of water for chrome tanning process, which is carried out without pickling and basification. Auxiliary chemicals like fatliquors are used to enhance the exhaustion of chromium during tanning process. The organoleptic and strength properties of the tanned leathers are on par with conventionally processed leathers. The process essentially involves utilization of the inherent water in the skin for tanning so as to attain sustainability with reduced pollution loads. Indian Patent application no. is 201611009091.

An improved eco-friendly process for curing of raw hides and skins
The present invention provides a salt free curing process for raw hides/skins. The curing process recited herein involves bio-macromolecules. Unlike the conventional salt based curing methods, this process does not add to the load of total dissolved solids (TDS) in the tannery waste water. The cured hides/skins can be stored upto 120 days. The invention has been applied for patent protection. (Indian Patent application no. 1491DEL2008).

The present invention provides a novel composition for chrome tanning of hides and/or skins thereby avoiding the conventional pickling operation and generation of large amounts of TDS in the waste water. In the process of the present invention the delimed hides and skins are treated with the claimed composition without affecting the tanning potency of the tanning salt followed by subsequent pH adjustment of the hides and skins with water only thereby eliminating the pickling operation and use of alkali for basification. The invention has been applied for Patent protection (Indian Patent application no. 2108DEL2008).

An improved process for making chamois leathers
The present invention discloses a process for making chamois leathers using modified plant oil. The process enables total replacement of fish oil resulting in final chamois leather free from fish oil odour. The main advantage of the process is that it is a versatile process, which is applicable to all kinds of raw materials viz. goat, sheep, cow and buffalo skins/hides. Considering that  chamois leather is one of the most popular articles of commerce, the process is envisaged to have enormous commercial importance.

The invention has been applied for patent protection ( Indian Patent application no. 205Del2008; Patent pending).

The invention relates to a non-enzymatic, sulfide free hair-save process for  loosening of hair/wool by way of using metal sulfite, followed by unhairing the hides/skins. The unique feature of the process is that loosening of hair is effected within a period of as low as 8 hrs. Moreover, the process takes place even at a pH 9, thereby avoiding the risk of grain getting harsh.  The process not only leads to a significant reduction in pollution load in the beamhouse effluent, but also ensures that the hair/wool, recovered as the byproduct of the process, may be used for beneficial purposes. 
The invention has been applied for patent protection.(Indian Patent application no. 380Del1999, Patent pending).

An improved process for making chrome tanned Leathers is provided whereby delimed pelts are treated with a mixture of conventional chrome tanning salt and alkali metal salt at a pH in the range of 5-5.5.  Complete elimination of salt is effected by this process. It is envisaged to have tremendous potential application in tanning industry, not only for improved chromium uptake during tanning, but also for substantial reduction of Total Dissolved Solids (TDS) in the waste stream.  The process is suitable for both hides and skins.
The invention has been applied for Patent protection (Indian Patent application no. 177DEL2002;Patent pending)

A novel process for preparation of dyed leather in more than one tone
The process relates to producing multi-tone dyeing on leather. It essentially regulates dye uptake selectively resulting in the formation of more than one tone on leather surface in a consistent, uniform and reproducible manner ensuring an economic option for enhancing aesthetic value of final leather. Thus the process finds enormous potential application in tanning industry not only for producing leathers for fancy articles, but also for upgrading low grade leathers, thereby resulting in substantial value addition.
The process has been applied for Patent protection (Indian Patent application no. 363DEL2001; Patent pending).

A novel process of aqueous finishing for waterproof leathers.
The process relates to the application of aqueous solution of film forming materials on conditioned wet leather before drying followed by conventional aqueous finishing, thereby providing a cost effective as well as eco-friendly method of finishing waterproof leather using aqueous system.
The process has been applied for Patent protection (Indian Patent application no. 221DEL2001; Patent pending)

A process for making crust for transfer coat finishing is disclosed whereby tanned leather is treated with selected amino resins either individually or in combination with selected condensation product of phenol and phenyl sulfones in the wet processing of leather, which is subsequently subjected to wet buffing operation to ensure preparation of suitable surface for transfer coat finishing. It is envisaged to have enormous application in leather processing industry for converting low grade tanned leathers into high value added finished items which can be used for shoe upper and leather goods applications.
The invention has been applied for Patent protection (Indian Patent application no. 343DEL2003;Patent pending)

A novel oxidative process  of using  ozone at alkaline condition is provided for the purpose of  loosening  hair within a time period as low as 30 minutes. The process provides an eco-friendly as well as time saving option for unhairing of hide/skin. 
The invention has been applied for Patent protection (Indian Patent application no. 315DEL2004;Patent pending).

An improved oxidative process is provided whereby oil treated skin is exposed to ozone to effect complete oxidation within a period of not less than 60 minutes to produce chamois leather.
The invention has been applied for Patent protection (Indian Patent application no. 312DEL2004; Patent pending).

Iron salts have been reported to be inexpensive and non- polluting with interesting tanning abilities. The previous attempts shows that even with proper masking salts a solo iron tannage can be achieved a shrinkage temperature of 80-97oC. In this process, arabinogalactan protein complex, which is a complex natural polysaccharide, is employed as masking agent along with ferric sulphate, tartarate, and phthalate as chelating ligands. The resultant leathers show a shrinkage temperature of 108 - 110oC. It completely eliminates the use of chromium to produce boil stable leather. Strength properties of the resultant leathers are comparable to that of conventional chrome tanned leathers.
This invention has enormous potential for application in leather processing industry for making wet brown leather. The new iron tanning is envisaged to be a potential alternative for Chrome tanning system.
The invention has been applied for patent protection (Indian patent application no. 645Del2006; Patent pending).

An improved process for making iron tanned leather is provided whereby pickled hide/skin is treated with Ferric salt in presence of chelating ligand, fatty acid and aromatic polycarboxylate under controlled conditions to adjust the final pH of the leather at 3.8-4 to obtain iron tanned leather. The leather exhibits a shrinkage temperature of 100 to106oC. It completely eliminates the use of chromium to produce boil stable leather. Strength properties of the resultant leathers are comparable to that of conventional chrome tanned leathers.
This invention has enormous potential application in leather processing industry for making wet brown leather. It is envisaged to be a potential alternative of Chrome tanning for making iron tanned leather.
The invention has been applied for patent protection (Indian patent application no. 643Del2006; Patent pending).

Conventionally tanned leathers are dyed in drum and this process results in producing conventional unishade leather. However, the increasing demand of fancy leather articles has over the years resulted in the requirement for leather with two-tone or even multitone effect. There are several methods to produce two tone or multi tone leathers however, each of them has its own limitations.
The present process essentially relates to the preparation of multi tone leathers by selective removal of colour from dyed leathers. The invention is directed to the selective blocking of the surface to the bleaching action of ozone with the help of coating of film forming materials leading to multitone formation on leather in a consistent and uniform manner ensuring an economic option for enhancing aesthetic value of the final leather.
It is envisaged to have enormous application potential in tanning industry not only for producing leathers for fancy articles, but also for upgrading lower grade leathers, thereby resulting in substantial value addition.
The process has the following advantages.
• It is a versatile process applicable to leathers of varying thickness and softness.
• The process produces more than one tone on leather surface uniformly and consistently.
• Unlike the hitherto known methods, the present process does not require any specialized skills, or any special equipment.
The invention has been applied for Patent protection (Indian Patent application no. 1764DEL2006; Patent pending).

Global environmental regulations are changing, almost forcing all processing industries to adopt greener and cleaner manufacturing practices. Proteolytic and ∝-amylase enzymes have been found to be useful for dehairing and fibre opening process, respectively. However, this process is a two step method, in which dehairing is performed by the proteolytic enzyme followed by fibre opening through carbohydrolytic enzymes.
The present invention integrates the two-step process into a single-step process, maintaining environmental sustainability. Various modes of application such as successive and simultaneous application of both the enzymes as well as application of a formulated enzyme product, which contains both proteolytic and carbohydrolytic enzymes, have been established. The extent of dehairing and fibre opening has been evaluated in comparison to the conventional or two-step enzyme based process derived skins/hides.
The invention has been applied for Patent protection (Indian Patent application no. 0197DEL2007).

The present invention relates to an eco-friendly unhairing composition and a process for unhairing animal skins therewith. It is a versatile composition, which can be employed by pasting or in the drum to all kinds of raw materials. The composition has application in the leather industry for eco-benign leather processing by replacing toxic chemicals in the pre-tanning process. Indian Patent Application No. 202111045115.