Why Fat Liquoring in Leather tanning process? classification of Tanning

Oil and fat soften the leather.  Fat Liquoring is one of the methods of making leather. During fat leaking, the level of fat leakage within the leather must be controlled.  In order to make different types of leather, you must be aware of the amount of fat liqueur used and what type of fat liqueur you should use.If you can't control the fat during the fat leaking operation, it may be harder or softer than the kind of leather you wanted to make.  Again the leather can be oiled.

In addition, fatty acid spews may be formed on the upper part of the leather.  Because fatty acids move from the inside of the leather to the outside and concentrate.  As a result, the white waxy or grizzly material is visible on the top.

The SATRA TM346 or EN ISO 4048 machine is used to determine the amount of grease.

Principles of Tanning process and features of tanning

Principles

The tanning method converts the protein of raw hides & skins into a stable material, which can not decay and is suitable for a wide variety of functions.

Most practitioners will provide some or all the subsequent characteristics of tanning as expected outcomes:

1.  Appearances: Dried raw pelt is translucent  (Semi-transparent), honny, but leather dries opaque or may change in color, e.g. chrome tanning.
2. Handle: Some degree of softness in co
   mparison to dried raw pelt.
3. Smell: Some tanning agents will introduce smell, e.g. cod oil for chamois leather, extract of plant materials for vegetable tanned leather or  aldehyde compounds.
4. Rise in denaturation temperature.
5. Resistance in putrefaction by microorganisms.
6. A degree of permanence (Stability) to the change.

classification of Tanning

Tanning Broadly classified into the following types:

 1. Mineral tanning 

1. Chrome
2.  Alum 
3. Titanium 
4. Zirconium
5.  iron
6. Mixed Mineral tannages 

2. Vegetable Tanning 

3. Other Tannages ( Oil, Syntan, Resins, aldehyde. Miscellaneous Tannages etc)

structure of  mineral tanning agents:

• Polybases = Chrome tanning agent, Aluminium tanning agents Zirconium tanning agents
• Polyacids = Phosphoric acid tanning agent, Silicic acid tanning agents