Raw Skins are the byproducts of meat trade & industry.Raw Leathers are converted to pelts which are ready for Tanning.
Conversion of Raw skins of cattle, sheep or goat skins can be explained as follows:
Tanning converts the protein of raw hides/skins to a stable material which will not putrefy and is suitable for variety of uses and applications
Types of Tanning:
Chrome Tanning is done using Chrome and appears blue-green and is called wet-blue and sold.
Vegetable Tanning is the oldest. Done with the use of Vegetable tannins obtained from barks / seeds of Vegetation and is sold as EI Tanned leathers in dry condition.
The above two types are semi processed and are not suitable to produce articles and are called as raw material. This are to be further treated with chemical and mechanical processes to get the “LEATHER” that can be used to produce articles.
The below are the processes that completes the tanning and yield the final leather
Drying – Removing the excess water for the next operation
Splitting / Shaving – Removing the excess thick lower flesh so as to obtain the required thickness of the final leather
Re tanning / Fat liquoring / Dyeing – additional tanning agents, oils and dyes are added in the wet drum to obtain particular feel, softness, depth etc. of the final leather characters specified for an article
Crusting – Uniformly dried stage is obtained for finishing the leather
Finishing process involves the following
Polishing – The surface is polished using mechanizes stone hard /velvet roller
Season Spray – Binders, Dye pigments, feel modifiers etc. are added to water to prepare season (which is like paint) that is to be sprayed on the surface to get the finished look in the required color.
Top sealing spray – To seal the pigments, binders etc to the leather binders/lacquers are sprayed so that color does not come of while rubbing the skin during usage of articles
Ironing and plating – To obtain the smooth surface
Tumbling – Is done if the surface of the leather is required in a natural pebbly look.
Embossing – To get different grain looks like crocodile, reptile leather or custom designs embossed look.