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What is Leather?
Leather is the fibrous corium
or structural part of animal skins as shown here in microscopic
cross-section.
Leather comprises:
-
Tanned Collagen
/ Proteins - 25% to 30%
-
Moisture - 60% to 65%
-
Oils and
Fat - 5% to 10%
The fibrous tissue is made up of a protein called "collagen". At a
molecular level the protein consists of three amino acid chains wound
together in a tri-helical formation. The molecules have a tendency to
line up end to end and to aggregate into larger macro-molecules called
"fibrils" and these, in turn, join up and twist together with others to
form fibers and ultimately the fiber bundles which can be seen by the
naked eye. The unique physical properties of leather come from the way
in which these fiber bundles are woven together into a three dimensional
network which extends throughout the bulk of the skin.
Here the fiber bundles are large and strong. They lie at varying angles
to the grain layer above. This
angle varies in different animals. This angle is known as the 'angle of
weave' and it effects the physical properties of the leather.
A lower angle of weave produces a softer, weaker
and less elastic leather.
In the leather tanning process, an important process called
"Fat-liquoring", in this process it uses
fats and oils to lubricate and soften the fiber structure of leather.
The manner in which the oils are introduced into the hide coat every
fiber. This is where leather gets its smell!
Leather is not leather until the skin or hide has been tanned.
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