At the Beamhouse:
The hides arrive at the beamhouse preserved in salt. Firstly, they will be soaked back and washed in wooden drums. Then they will go through liming and unhairing, the hides swell and the hair is dissolved. Chemically, the collagen fibres in the hide undergo a partial alkaline hydrolization and become gelatinous.
Two mechanical operations follow: Fleshing removes the subcutaneous and adipose tissue adherent from flaying the hide, and Splitting divides the hide in two through the substance, resulting in the grain side and the split from the flesh side.
At the next stage the hides are loaded into drums to be prepared for Tanning: Deliming promotes the removal of lime and Bating is the enzymatic “cleaning” of hide fibbers. Then the hides are further acidified in the Pickling using formic and sulphuric acid. The collagen fibres are now reactive to bond with a tanning agent.
Conventionally the tanning agent is a chrome salt, whereas for our vegy leathers a metal free innovative and environmental friendly alternative is used. It is based on modified glutheraldehyde, synthetic organic tannins and resins and vegetable extracts. All the scraps and waist waters are metal free and can be regarded as domestic organic sewage and sludge, they can even be composted to a nitrogen rich soil nutrient.
Unloaded from the tanning drums, the skins are compressed to remove excessive humidity in the Samming machine. The skins are now stabilized and have acquired mechanical, thermic and microbiological resistance, they are called wet-white at this stage. The batch is then carefully sorted skin by skin with respect to the grain quality and it is shaved from the flesh side until desired thickness in the Shaving machine.
Again the skins are loaded into drums and undergo the Dyeing process, which provides specific properties regarding behaviour, look, resistance and performance:
1. re-tanning: further addition of tanning agents (vegetable extracts, synthetic tannins and resins) yielding tightness and firmness
2. dying: combination of the dyestuff to achieve desired color
3. fatliquoring: lubrication of the fibbers, providing tearing resistance, elasticity and softness
Drying & Finishing
The leather is then set out to remove excess water and hanged to dry at room temperature. When dry, the contour of the skin is trimmed and it passes through a continuous softening machine. The Finishing operations are the final treatment of the leather in order to achieve the desired superficial effects, color, shine, feeling, texture, etc. Typically, waxes or dyes are applied in spray-gun machines followed by plating in a press and milling in a wooden drum until the crushing of skin against skin yields the desired texture and softness. Only the hands will tell!