| abstract |
Prodn. of leather and hides involves: (a) pretanning with an aldehyde tanning agent (I); and (b) retanning with a mineral tanning agent, with omission of the defatting, pickling, deliming and neutralisation steps. The novelty is that (I) comprises 2-8C aliphatic, 8-14C aromatic or 9-16C araliphatic dialdehyde, 2-8C aliphatic monobasic aldehydocarboxylic acid, 3-10C aliphatic mono- or di-basic keto-carboxylic acid, their acetals with 1-10C aliphatic mono- or dihydric alcohols, opt. reacted with 1-50 mole ethylene oxide and/or propylene oxide/OH gp., or mixts. of these cpds. (I) esp. is 2-4C aliphatic dialdehyde(s) and/or their acetal(s). |