Leather is one of the last remaining natural materials in a world of Teflon, Rayon and Rubbers. People love leather for its soft feel, wearability and prestige.
Leather today is so versatile; it can be transformed into a wide range of different things such as shoes, saddles, gloves, lounges etc. The texture of leather can also be changed for example; you can turn a normal piece of cow hide into something that resembles crocodile skin with all the new grain pattern embossing technologies and all this from a natural skin from a cow, buffalo, kangaroo etc. Cow & Buffalo hides are the only hides used for Upholstery Leather. There are various types of upholstery leather being used in the furniture upholstery industries.
Leather Processing
- Leather processing is very complex. After removing the leather skin from the beast they are salted immediately to prevent initial bacteria growth. The skins are then sent from the abattoir to the tannery.
- Once the hides have arrived at the tannery the following process takes place. The leather is soaked in a Chromium Sulphate Solution to clean the raw hide.
- The leather hide is then soaked in a Liming solution to open the fibres of the leather for the ease of removing the hair and unwanted part of the hide. This also kills all the bacteria.
- The next step is to mechanically split the hide so that the hide is clean and even all over. (This is also known as fleshing).
- Once this is done the leather is de-limed to remove the unwanted chemicals from the liming process.
- The leather hide is then put through another wash of acids and solvents so as to make it clean and ready for tanning.
- The tanning process is now ready to begin.
Tanning Process
The tanning process consists of various treatments.
- Preservation by cross–linking the fibres (also known as tanning). This is achieved by either mineral, aldehyde or oil and vegetable tanning.(Mineral Tanning is commonly used for Upholstery Leather)
- Samming or squeegeeing the water and chemicals out of the leather.
- Splitting – A splitting machine slices thicker leather into two layers. The layer without a grain surface can be tuned into suede or have an artificial grain surface applied.
- Shaving – Adjusting the thickness of the leather
- They may now re-tan again to adjust the various features in the leather or neutralise the chemicals from the leather and continue with the processing.
- Dyeing of the leather for desired colour. This is mostly done with penetrating dyes, although some leathers are only surface dyed.
- Fat liquoring –Treatments of fats and oils to adjust the leather’s softness.
- Drying – This is done through a drying tunnel or on a rack.
- Staking – Mechanically softening of the leather.
- Buffing & Brushing – in some cases the grain surface is buffed to produce a very fine nap, example nubuck leathers.
- Finishing – Applying more pigments and binders and also polyurethane finish coats as well as correcting the grain surface. (Also known as embossing).
- Plating – Smoothing out the top-coats.
- Final Grading – This will depend on colour intensity, uniformity, feel, thickness, appearance and natural marks on the hide.