How can we formulate a leather finish ?
It is necessary to distinguish between self coloured leather finidhing lacquers and clear lacquers frequently incoporating transparent pigments which emphasize the appearance of the leather. In the first case inorganic pigments are generally used ( mainly as preparations ) because of the high demands made on tint uniformity and opacity. In the case of clear lacquers, organic pigments with high colour brilliance are more usual.
Water based leather finishes have ecological and processing advantages. They used to be formulated on a casein basis. Nowadays the are produced mainly with synthetic film formers, preferably polymer resins with added surfactants. Solvent based systems are still of great importance classically with cellulose derivatives as film formers.
These have recently been replaced by [o;yurethanes with which outstanding flexibility can be achieved without using plasticizers such as phtalic, adipinie or [hosphoric acid esters which are usually necessary.