Caustic soda in tanning
Caustic soda in Leather Manufacturing: caustic soda is a highly reactive alkali
is widely used in various industries.
Caustic soda has a faster and stronger reactivity than other alkali materials.
The tannery or leather process makes the corrosive skin a stable,
permanent, and flexible natural material for many applications.
This natural material is called “leather”, which has many uses.
Leather dressing or tanning has several stages during which the skin turns into
Souse and soaking
Caustic soda in tanning
At this stage, the skin will soda from salt.
Coldwater is passed through the soda salt skin and the salt dissolves in water.
With this, the skin becomes aqueous.
In this process, some proteins in the skin are removed from the skin with blood
and other water-soluble proteins.
The exit of these proteins increases the quality of the skin.
At this stage, antibacterial agents (often chlorine compounds) are commonly used.
And, substances such as sodium sulfide (S2Na) or sodium
tetrasulfide (۴ s2Na) can be used in water.
Until the root of the hair becomes loose.
then, water-soluble proteins are removed from the skin,
the skin returns to its natural state by absorbing water.
And it will be ready for the next steps.
At this stage, lime operations are performed on the skin.
By raising the pH of the blood, the roots of the hair are loose and help
remove excess proteins and fats.
By placing the skin in this environment, the keratin molecules of the hair are
broken down without skin collagen damage.
After the limescale process, it is necessary to remove all unnecessary skin tissues.
At this stage, using a device called the muscle, meat and other extra tissue
remaining on the skin separated from it And cause the chemicals that
are used in the next steps to uniformly penetrate the skin.
Leather Lining and Curling
After decay, you must remove wool and hair, and other proteins from the skin.
To do this, they put it in a solution of lime and add a little sodium sulfide.
It combines hair and hair wrapping.
In addition to sodium sulfide, other compounds such as methylamine,
sodium sulfide, and sodium carbonate are also used;
These materials are used to facilitate the process of manipulation.
The remaining lime from the previous step must be completely removed
as it may cause the staining phase to be difficult.
For this purpose, chemicals used in the leather industry such as ammonium
salts, sodium bisulfite,Sulfuric acid.
The skin is eaten in an alkaline solution with ammonium salts,
which increases the effect of enzymes.
And the surface of the skin is smooth and clean.
Meanwhile, the flexibility of the skin also increases.
The skin of some animals is greasier and requires a separate step to remove fat.
At this stage, sodium hydroxide is usually used to convert fat to soap
and to wash it with water.
For coloring leather, organic colored materials, and inorganic colored
materials such as zinc oxide and lead chromite are used.