Single-bath chrome tanning General
One-bath chrome tanning is a chrome tanning method primarily used for leather underlays. During the 24-hour chrome tanning process, 1.5% of the chromium sulfate is absorbed into the leather, creating its distinctive greenish-blue color. Outer leather is more likely to be tanned (vegetable) and thus has a tan or light reddish-brown color. The color of the underlay is then only very slightly discernible on average.
Properties of leather through single-bath chrome tanning
It is particularly important to consider the following parameters in the leather being tanned: pH, chromium oxide content, alkalinity, and the presence/type of masking. Depending on the target leather type, certain final values of these parameters must be targeted to achieve different properties.
The tanning agents used in the one-bath chrome tanning process make the leather smoother and more tear-resistant. With the help of chromium salts, the pickled, untreated hides are then transformed into smooth, supple grains.
One-bath chrome tanning vs. two-bath chrome tanning
For a short time, single-bath chrome tanning was replaced by two-bath chrome tanning. However, this has since become less common again because the chromium(VI) compounds used made negative headlines due to their toxicity.
additional sources (accessed 14.11.2018)
- lederpedia(dot)de/lederherstellung/tannung/masked_chrome_tannins
- lederpedia(dot)de/lederherstellung/tanbung/chrome_tanning_in_the_practical_process
- Josef Jettmar - Combination tanning of tannery, white tannery and chamois tannery
- chemgapedia(dot)de/vsengine/vlu/vsc/de/ch/9/mac/netzwerke/vernetzung/ionisch.vlu/Page/vsc/de/ch/9/mac/netzwerke/vernetzung/chromgerb.vscml.html
- D. Balaanyi, O. Gerngroß, etc. - Mineral tanning and other non-vegetable tanning methods: Tanning
