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HIDE |
Careful selection is necessary to ensure satisfactory final material characteristics
(grain, surface defects, etc...) |
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FLAYING |
In this step the skin of the animal is extracted (skinning). Skinning may be performed
manually (which may leave knife and tool marks on the material) or mechanically (which is in extensive use in Europe). |
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SALTING |
To promote conservation of the hide, layers of Sodium Chloride (common table salt
(NaCl)) are placed between hide layers to protect the structure of the hides. |
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SOAKING |
The skins are washed of blood, mud, etc. Well water from the source is preferable
to surface water sources |
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STRAIGHTING |
Na2S (Sodium Sulfide) is used to shave the hides, along with Ca(OH)2 (Calcium Hydroxide)
and NaOH (Sodium Hydroxide) in basins or in drums. |
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LIMING |
The hides are bathed in lime to effect a swelling of fibers and colagenum fibers,
as well as the dissolution of hair, fats, etc. |
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FLESHING |
Performed manually or mechanically, this step is necessary to eliminate residual
organic material from the endodermis to avoid bacterial growth. |
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DELIMING |
All lime is removed from the hides using ammoniacal salts (Sulphates of Ammonium
or Ammonium Chloride) or acid salts (such as Sodium Bisulphite). This step also smoothes the skin. |
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BATING |
I Part of the pre-picklet one: by means of enzymatic actions the colageno fibers
are alflojan to give to smoothness and firmness of grainside, etc. |
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DEGREASING |
In this step, the fats that would later inhibit the tanning process are degraded.
Mineral oils or chlorinated paraffin are used to avoid undesiderable fat spots. |
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PICKLING |
Pickling is used as a conservation method and is performed with: 12-15 % common salt
(NaCl) and 1.5-2.0 % sulfuric acid (H2SO4). The process is similar to the old and well-known process performed
for food storage using acids and salt. |
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TANNING |
Tanning, by definition, is the transformation of any skin into leather (including
the prevention of rotting). Salts of elements like Chromium, Titanium, Aluminum are used. Also some vegetal extracts
may be utilized. |
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SAMMYING |
The leather slips to facilitate the divided operation of in blue (Chrome's color)
or of reduced, to leave it to the suitable thickness. Here is where the wet phase ends. |
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SPLITTING |
The tanned leather is divided in two layers (grain side and flesh). The removed flesh
is the inferior part of the leather and can be futher subdivided one or more times (called splits) depending on
the leather's thickness. |
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SHAVING |
This step results in leathers of uniform thickness. This is a completely mechanical
process. |
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NEUTRALISATION |
After the neutralization (unacidulation) we obtain a leather tanned to chromium,
parked reduced and slipped (the leather is still humid). |
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RETANNING |
Retanning in drums results in final leather characteristics not obtainable by a single
tanning (a fuller leather, more smoothness, to favor the dye equalization). |
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DRUM DYEING |
By adding color to the water of the drum, the dye penetrates into te cross section
of the leather to avoid clear cuts in the edges. |
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GREASING |
After tanning the leather is made hard because the fibers have been united. The greasing
process is performed to effect absorbtion of greasy substances to obtain a smoother and more flexible leather. |
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DRYING |
Drying is the elimination of the humidity of the leather to be able it to work appropriately.
It is a very important process for the later quality of the desired article. |
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PRE-GRADING |
Pre-grading is a first visual inspection and grading by quality, thickness, grain,
etc. to allow for sorting of the product to different final destinations. |
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PRE-FINISHING |
Here the leathers are prepared for the final finishing steps, including softening,
trimming, grinding, wiping, etc. |
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FINISHING |
Aniline finishing is used for the best leathers, while pigmenting is used to equal
the superficial tone of the same ones. From this step forward the leathers have their own article name. |
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GRADING |
This last selection is made solely on the basis of defects in the grain side, since
the final article is complete and were leathers chosen for the same itself. |
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MEASURING |
After preparation by qualities, the surface of each piece of leather is measured,
the articles are packed (according to the size) at the rate of 1/2 dozen, 1 dozen, or 2 dozens per bundle. |
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SHIPPING |
Once packed and invoiced the articles for shipment, the articles are sent to customers.
Shipping sizes range from pallets via air cargo to cardboard boxes by courier. |
