Condensates for the retanning of fe-tanned leather.

摘要

Use is claimed in the post-tanning of iron-tanned leather of condensation products of (A) sulfonated aromatics; (B) aldehydes or ketones; and optionally also (C) non-sulfonated aromatics, urea or urea derivatives with the proviso that the content of naphthalenesulfonic acid-formaldehyde condensates and phenol-formaldehyde condensates is below 25 (especially below 5)% of the total weight of condensation products. Independent claims are also included for: (1) leather of iron content 1-7 wt.% containing a condensation product of (A)-(C) as above; and (2) production of leather especially of softness above 15 units (IUP/36) obtained by post-tanning iron-tanned leather with condensation products of (A)-(C) as above.