Carmine GAETA | Patents

Several environmental problems related to the use of Cr(III) in manufacturing processes of hides have induced tannery workers to reduce the amount of used metal or to use alternative free-metal tanning. Following these directions, in this patent are disclosed any tanning processes for preparing any kind of leather in which p-sulfonated calix(n)arene derivatives (with n = 4-20) are used. p-Sulfonated calix(n)arene derivs. (with n = 4-20) are used as acid for pickling skins in leather pickling process or as synthetic tans in pre-tanning, tanning or re-tanning processes. In another embodiment, p-sulfonated calix(n)arenes (n = 4-20) are used together with metal salts (e.g. Cr, Al, Ti, Zr, etc.), or any vegetable tans (e.g. mimosa, quebracho, sumac, myrobolans, etc.) as tanning mixtures. In a further embodiment, p-sulfonated calix(n)arenes (n = 4-20) are used to fix fatliquors into the leather in fatliquoring processes or to fix dyes into the leather in dyeing processes. Also disclosed are processes in which mixtures of any composition of p-sulfonated calix(n)arenes (n = 4-20) prepared by any synthetic process, are used.