Prodn. of chrome free soft leather - by treatment with oil, fat or fatty oil before tanning

摘要

In prodn. of chrome-free soft leather by tanning the skins with known vegetable and/or synthetic tanning agents, the limed, lime-free and bated skins are treated before tanning with 2-20 wt.%, w.r.t. the leather, of mineral oil(s), fat(s) or fatty oil(s) and/or mineral oil derivs. reactive with the NH2 gps. of the leather proeteins, at a temp. at which these agents are liq., but at least 20 deg.C below the shrinkage temp. of the leather. Treatmeht is for 0.5-7 h, depending on the thickness of the leather. ADVANTAGE - Environmentally harmful chrome wastes are avoided. Rapid bonding of the tanning agent, causing over-tanning of the leather surface, is prevented.