What Is Fatliquors ?
Basically, this is oils and fats that are used in the leather industry when tanning leather hides.
All the natural fats have to be removed, if these were not removed the hides would smell horrible and go rotten. There are several different methods for removing these natural fats, one includes a solvent bath, this dries out the raw hides fully and at this stage the skins looks somewhat horrible dry and hard to touch almost like a brittle bit of skin.
It’s at this stage that fatliquors are replaced to make the skin soft and supple once again and these are added to the collagen fibres of the leather. This keeps the collagen fibres from drying out and keeps the leather soft and supple for many years to come, depending on the quality of the fatliquors being produced and used will depend on the finished quality of the hide and how long this stays soft and supple.
Looking at the reverse of leather under a microscope, the leather looks like a tangled mess of fibres almost resembling a scouring pad, but much finer and smaller, these fibres are all held together with collagen protein bonds.
Fatliquors are classified into two categories, non-emulsion, and emulsion types. Non-emulsion types includes items such as many types of natural oils, such as beef tallow oils, fish oils, animal oil – lard, mutton tallow and the beef tallow, vegetable oil, olive oil, wax, mineral oil, wool grease, paraffin wax etc.
Emulsion types include, amphoteric ones such as, amino carboxylic acid base oil and betaine compounds; and non-ionic ones such as polyethylene oxide derivatives. Phosphated oil and aliphatic acid condensate base oil; cationic ones such as aliphatic acid amine base oil; anionic type ones such as sulphated oil, sulphited oil, sulfonated oil and soap.
Leather needs to be kept nourished and protected as much as possible so the leathers protein fibres can retain its suppleness keeping the fatliquors locked in for as long as possible.
Massaging the leather also helps to keep the leather soft and supple, this can be done with a special massaging roller, by going over the surface massaging this into the leather as you go.