KASUR
TANNERIES POLLUTION CONTROL PROJECT (KTPC)
- A DOCUMENTARY
All animal skins
consist of three layers, the epidermis ( cuticle or outer layer),
a layer of fatty tissues, and the inner layer, or corium. It is the
latter from which the leather is made, and the objective of the tanning
process is to strip off the two outer layer of the skin and subject
corium to the action of the agent; which converts it to the semi-soluble
protein to the tough insoluble mass known as leather. The principal
constituents of the corium is the protein collagen, C102H149N31O38,
which in contact with warm water , is converted to lyophilic colloids
gelatine and glue. When subjected to the tanning agent ,
it undergoes a transformation the exact nature of which is unknown,
and becomes insoluble in water, tough, flexible and highly durable.
The vegetable tannins
are complex glucosides of tannic acid, obtained from the various
tree barks, wood, and fruits. The tanning agents are usually produced
by the water extracts of crude material and concentration of extracts.
Salts of metal chromium form the second important group of tanning
material. These may be in trivalent or hexavalent form. Aluminum
sulfate is used for the specialty products. Oil form the third group
but they are only used in the production of the special type of
the leather, particularly chamois.
Vegetable tanning sole, harness, belting,
luggage, upholstery.
Chrome tanning Upper leather, garment leather, gloves.
Combined ( vegetable & chrome) some sole and upper leather.
Alum or alum-chrome White upper leather, furs.
Oil Chamois.
The tanners of kasur produce leather for the local market and it
is of just common type. Thus almost every tanner does chrome tanning
for leather production, as it is the modern trend too. The chrome
tanning is cheaper, less time consuming and still gives better quality
leather than vegetable tanning.
