Investigations on the general properties of biomass-based aldehyde tanned sheep fur for its selective post-tanning processing

Dialdehyde sodium alginate (DSA) is an alternative chrome-free tanning material for fur production. To obtain satisfactory resultant fur and provide suggestions for the usage of DSA in fur making, the general properties of DSA tanned sheep fur were systematically investigated. The tanning mechanism of DSA was analyzed and it was verified that DSA was mainly combined with collagen fiber by forming Schiff base covalent bonds while supplemented by a small number of hydrogen bonds and ionic bonds. Due to the acid sensitivity of Schiff base structure, DSA tanned fur had poor resistance to acid rinsing but had excellent resistance to washing and good fatliquoring performance. Also, it had good resistances to yellowing and reductant. After being retanned by chrome tanning agent, the fur was capable of enduring a high-temperature dyeing process (68 °C for 8 h). Overall, DSA tanned sheep fur had favorable properties under appropriate post-tanning processing conditions to manufacture light-colored or dark-colored fur products with desirable physical properties.