The Chemistry of Leather Care

 Leather can be thought of as a non-woven mass of fibrous collagen protein that is derived from the skin of animals and that has been rendered biorefractive. An animal skin is made biorefractive and thereby converted into leather by the tanning process. The tanning process permanently incorporates what amounts to biocide into the collagen protein. Other desirable characteristics are imparted to the leather through fatliquoring, coloring, dressing, waterproofing, shaping, and working.

Fatliquoring is the process of incorporating fats, greases, and oils into the body of the leather. The presence of fats, greases, and oils in leather lubricates the fibers and tends to waterproof the leather. Without enough internal lubrication, the fibers will abrade and break due to friction, and the leather may crack.

Leather is given a color by means of dying or pigmenting. Depending upon the means employed, the coloration can be incorporated through the entire thickness of the leather, or it can be concentrated at and near the surface.

Dressing is a surface finish that is given to the material. The surface finish is a continuous organic matrix distinct from the protein fibers. That organic matrix can range from a latex paint to a wax. Dressing always refers to that which is the outmost layer of organic matter of the leather. Thus it is possible for a dressing to be "dressed," since it is possible to apply a wax polish to a surface of painted leather. Prior to wax polishing, the organic matrix that is the paint outer layer of the leather was the "dressing."

Working the leather refers to the repeated flexing of the leather in order to reduce stiffness. This is an entirely mechanical process.

HOW TO THINK OF CHEMICALS FOR LEATHER CARE

All chemical treatments of leather fall into one or more of these categories: substitute fatliquors, surface dressings, waterproofers, and cleaners.Shearling Jackets Coats