Crust Leather Production Process with flow sheet

Raw Materials

The main raw materials for production of crust leather from wet-blue leather stage are wet-blue leather, oils, synthetic tannins, vegetable tannins, aniline dyes, sodium bicarbonate, sodium acetate and formic acid.

Flow sheet of crust leather production


The processes that follow from the wet-blue leather stage to produce crust blue leather are mentioned below.

a) Trimming

Rough edges of leather are trimmed to remove uneven, and ragged edges.

b) Splitting

Thick hides will be split by splitting machine. The top layer is called the grain part and the bottom layer, flesh part.

c) Shaving

Thickness of splits is adjusted in a machine fitted with shaving blades which reduce the substance of the leather according to the desired thickness.

d) Retanning, fat liquoring and dyeing

This is a combined process in which the semi-finished leathers will get a final tanning and some further treatment.

e) Setting out

As in sammying thin process involves the removal of moisture content. Creases are

also removed at this stage.

f) Drying

The damp leather is dried. In hot weather natural drying is preferred.

g) Conditioning

After drying, leather becomes stiff. For further operations, a certain degree of conditioning, i.e. moistening the leather to 28 to 30 per cent moisture content, is essential. Then, staking and sorting unit operations follow.

In the production of crust leather substantial effluent is generated. Full or partial treatment of effluent is essential to avert its adverse impact on environment.

List of Main Equipments

Drum (retaning / dyeing)

Wringing machine

Setting out machine

Spliting machine

Shaving machine

Vacuum dryer, 2-plate

Drying machine, Tunnel drier

Measuring machine

Balance, heavy duty

Boiler

Scales, hand tools transport wagons, pallets, work tables & pipings

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