Bayer Aktiengesellschaft

Joachim Kochta

Bruno Bomer

Harro Traubel

Gunter Sackmann

Tillmann Hassel

Hans-Albert Ehlert

Bernhard Wehling

Franz Schade

Henricus Slaats

Peter Schindlmayr

Harro Tr Aubel

Wilhelm Krummel

Herbert Burkhardt

Thomas M Unzmay

Wilhelm Kr Ummel

The invention relates to reaction products prepared from

Polyisocyanate addition compounds containing cyanamide groups and their

Copolymers containing incorporated radicals of long-chain alcohols and neutralized carboxyl groups are suitable as retanning agents for leather. They result in an excellent combination of water repellency, softness and grain tightness.

Softening and waterproofing retanning agents

The present invention relates to a process for retanning chrome-tanned leather comprising applying to leather a reaction product of (a) at least one glycerol monoester of a saturated C.sub.12-18 monocarboxylic acid, (b) at least one diisocyanate selected from the group consisting of toluene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate, and (c) dimethylolpropionic acid, wherein (i) the components (a), (b) and (c) are so selected that the molar ratio of the isocyanate groups of component (b) to the sum of the hydroxyl groups of components (a) plus (c) is about 0.5 to about 1.05 and (ii) the molar ratio of compound (c) to compound (a) is about 0.7 to about 1.5 and wherein (iii) the carboxyl groups originating from compound (c) are at least partly neutralized.

Use of ester urethanes for retanning

In the production of chrome leather, a pretreatment of delimed and bated pelts with condensation products not having a tanning action leads to substrates which, without any problems, can be mechanically dewatered and shaved or split and shaved. The properties of the leathers produced therefrom by chrome tanning do not differ from those of leathers which have been conventionally chrome-tanned and shaved.

Process for producing chrome leather

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Bonn, Germany

Joachim Kochta