What is leather?
A: Leather is a strong, flexible and durable material obtained from the
tanning, or chemical treatment, of
animal skins and hides.
How long has leather making been practiced?
A: For more than 7,000 years.
Who are the leading producers of leather today?
A: China and India.
Animal rights groups claim that modern commercial
leather making, and the consumption of its products is what?
A: Unethically killing animals.
Critics of tanneries claim that they engage in
unsustainable practices that do what?
A: Pose health hazards to the people and the environment near them.
The processing stages of tanneries use thousands of
liters of water for what?
A: For one hide or animal skin.
The leather manufacturing process is divided into what
three fundamental subprocesses?
A: Preparatory stages, tanning, and crusting.
The preparatory stages are when the hide is prepared
for what?
A: Tanning.
Preparatory stages may include what?
A: Soaking, hair removal, liming, deliming, bating, bleaching, and
pickling.
Tanning is a process that stabilizes the proteins,
particularly collagen, of the raw hide to increase what?
A: The thermal, chemical, and microbiological stability of the hides and
skins, making it suitable for a wide variety of end applications.
The principal difference between raw and tanned hides
is that raw hides do what?
A: They dry out to form a hard, inflexible material that, when rewetted,
will putrefy, while tanned material dries to a flexible form that does not
become putrid when rewetted.
The typical process sees tanners load the hides into a
drum and immerse them in a tank that contains what?
A: The tanning "liquor".
The hides soak while the drum slowly rotates about its
axis, and the tanning liquor slowly what?
A: Penetrates through the full thickness of the hide.
Once the process achieves even penetration, workers
slowly raise the liquor's pH in a process called what?
A: Basification, which fixes the tanning material to the leather.
The more tanning material fixed, the higher the
leather's what?
A: Hydrothermal stability and shrinkage temperature resistance.
Crusting is a process that does what?
A: Thins and lubricates leather.
It often includes a what?
A: A coloring operation.
Crusting culminates with a drying and softening
operation, and may include what?
A: Splitting, shaving, dyeing, whitening or other methods.
Leather can be oiled to improve its what?
A: Water resistance.
Formaldehyde has been used for tanning in the past; it
is being phased out due to what?
A: Danger to workers and sensitivity of many people to formaldehyde.
Chamois leather is a form of aldehyde tanning that
produces what?
A: A porous and highly water-absorbent leather.
What is patent leather?
A: Patent leather is leather that has been given a high-gloss finish by the
addition of a coating.
Suede is made from what?
A: The underside of a split to create a soft, napped finish.
It is often made from younger or smaller animals, as
the skins of adults often result what?
A: In a course, shaggy nap.
Today, most leather is made of what?
A: Cattle hides, which constitute about 65% of all leather produced.
What other animals are used?
A: Sheep (about 13%), goats (about 11%), and pigs (about 10%).
Horse hides are used to make what?
A: Particularly durable leathers.
Lamb and deerskin are used for what?
A: Soft leather in more expensive apparel.
Deerskin is widely used in what?
A: Work gloves and indoor shoes.