Leather Processing

A process for curing cum dehairing of hide/skin
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.


A waterless bioprocessing for dehairing and fibre opening in leather manufacture
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.

An improved process for making retanned leather with dyeing effect
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.

A process for the preservation of hide and/or skin
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.

A leather making process using plant material
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

An improved Chrome Tanning Process
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.

A waterless tanning process for making leather
Disclosed herein is a process of tanning delimed/pickled pelt without adding any water. The pelt is treated with conventional tanning agent and is then subjected to a treatment of solvent having LD50 (median lethal dose) value not exceeding 20000 mg/kg. The solvent can be reused. The quality of leather is at par with that manufactured by conventional process. The general appearances such as grain and colour are comparable with conventional wet blue/vegetable tanned leathers. The process provides an alternative way for tanning with possible reductions in pollution loads. It is likely to have immense application in leather industry in reducing the effluent discharge and water requirement. Indian Patent application no. is 1786DEL2014.

A Process for fibre opening in leather making
Disclosed herein is a process for fibre opening in leather making using ionic liquid. The unique feature of the process is that it involves the employment of select group of ionic liquids to ensure complete removal of interfibrillary material, thereby adopting a cleaner, greener and user-friendly approach for fibre opening. The invention is envisaged to eliminate environmental challenges of using lime. It also strives to combat the challenges of lack of skilled labors and the need for maintaining controlled environment required for enzyme application. The process is envisaged to have immense application in tanning industry in ensuring eco-benign fibre opening at a faster rate with a focus on cleaner leather processing. Indian Patent application no. is 1005DEL2014.
An improved process for uniform dyeing of leather
Leather being a natural material, often does not produce consistent physical properties including appearance. The situation is more complicated when leathers of different batches are pooled together for dyeing. Variations in colour intensity of dyed leathers is a major technological problem in leather making. This poses serious economical problem in the case of leathers where dyeing colour decides the final quality of leather. The present invention provides process of leather dyeing using an aqueous suspension of M2+/Al3+ layered double hydroxide (LDH) thereby minimizing variations in colour of the leathers ensuring consistency both within a batch of leathers and batch to batch of leathers, without adversely affecting other characteristics of the leathers and thus preventing productivity and economic loss. Indian Patent application no. is 2568DEL2014.
A Process for lubrication of hide/skin by ultrasound
Disclosed herein is a process for in-situ emulsification and subsequent distribution of natural fatty material available in hides/skin matrix by ultrasound, thereby effecting lubrication of hide/skin fibres without adding any external fat. Conventional degreasing is avoided to ensure that the available natural fat is available for lubrication. It results not only in process economy, but also in reducing pollution load by ensuring elimination of fat in the effluent. The process finds enormous application in leather processing industry to ensure effective lubrication with the natural fat present in hides/skin matrix. Indian Patent application no. is 3128DEL2014.
An improved tanning process
Disclosed herein is a process of mineral tanning process in aprotic solvent medium without using any water. In this process, the solvent enables a complete diffusion of the tanning agent during the tanning process, following which the tanning agent is fixed to the substrate by using conventional chemicals. The solvent can be reused, thereby eliminating the effluent load as well as the TDS problem associated therewith. The process finds potential application in leather processing industry for the purpose of waterless tanning. Indian Patent application no. is. 2704DEL2014.
A Process For The Rehydration Of Crust Leather
Disclosed herein is a process for rehydration of crust leather using eco-benign enzymatic products eliminating formation of harmful substances in leather. The process ensures a reduction of rehydration duration to the extent of 25 to 70 %, thereby resulting in increase in productivity. It is envisaged to have wide application in leather processing industry as an eco-friendly and effective option for further wet processing of crust leather in aqueous medium especially for the purpose of dyeing of dried crust. (Indian Patent application no. 796Del2014.)
An Improved Post Tanning Process For Leather
Disclosed herein is an improved process for the manufacture of leather using non-aqueous fluid employed in the post tanning process for completely replacing water. The process is designed in such a way as to use conventional post tanning chemicals in the non-aqueous fluid. The invention is envisaged to have immense application in tanning industry for curtailing the pollution load of the effluent by ensuring higher diffusion of chemicals on the one hand and focusing on recycle as well as reuse of the non-aqueous fluids used therein. Compactness of fiber bundles in the crust leathers match with those with conventional water based processes. (Indian Patent application no. 3812Del2013.)
A Zero Emission Chrome Tanning Process for Leather Making
The process provides an eco-friendly option of chrome tanning whereby total utilization of chrome is ensured. The methodology eliminates total usage of sodium chloride and mineral acids for pickling and ensures total utilization of tanning material through suitable process interventions for recycling without resulting in emission or discharge of process chemicals or used liquor. The process has been applied for patent protection
(Indian Patent application no.1356DEL2011).
Zero Wastewater Discharge process for Pretanning operations
Disclosed in the present invention is that the waste streams from soaking, liming, deliming including washing prior and after deliming and pickling are segregated and screened for removing gross solids. They are treated by electro-oxidation with or without UV treatment. The treated sectional streams are reused appropriately taking into account the hydraulic load and pollution load from each unit process, and process system. The reuse can be carried out continuously to attain zero wastewater discharge.
The invention has been applied for patent protection (Indian Patent application no. 2698DEL2010).
A synergistic degreasing composition and an improved process for aqueous degreasing of hides and skins therewith
Disclosed in the present invention is that the waste streams from soaking, liming, deliming including washing prior and after deliming and pickling are segregated and screened for removing gross solids. They are treated by electro-oxidation with or without UV treatment. The treated sectional streams are reused appropriately taking into account the hydraulic load and pollution load from each unit process, and process system. The reuse can be carried out continuously to attain zero wastewater discharge.
An enzymatic process for the removal of fleshings from hides and skins
Disclosed in the present invention is that the waste streams from soaking, liming, deliming including washing prior and after deliming and pickling are segregated and screened for removing gross solids. They are treated by electro-oxidation with or without UV treatment. The treated sectional streams are reused appropriately taking into account the hydraulic load and pollution load from each unit process, and process system. The reuse can be carried out continuously to attain zero wastewater discharge
A lime and sulphide free process for the preparation of pickled stingray fish skin
In view of the fact that the conventional lime-sulphide based depigmentation process for stingray fish skin adds to enormous pollution load, a lime-sulphide free dodecyl sulphate based process has been provided as an eco-benign option for producing pickled stingray fish skin. The pickled skin can be further processed to prepare stingray leather that finds potential application in making several fancy leather goods.
The invention has been applied for patent protection (Indian Patent application no. 1901DEL2009).
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).
A novel composition for chrome tanning of hides/ skins 
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).
An improved process for the unhairing of hides/skins
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
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)
 An improved process for making crust leather for transfer coat finishing
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 for the unhairing of hides/skins.
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 for making chamois leather.
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).
A process for making iron tanned leather using natural polysaccharide
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
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).
An improved process for producing leathers in more than one tone
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).
An improved process for dehairing and fibre  opening of hide/skin
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).


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