Study On The Tanning Mechanism Of Novel Chrome-free Tanning Agents And The Synthesis Of Acrylic Retanning Agents

A series of novel chrome-free tanning agents were synthesized with erea, glyoxal, glycine and melamine. Their structures were confirmed by FT-IR; The tanning mechanism was studied by amino acid analysis. The molecular structures of these chrome-free tanning agents were simulated. The shrinkage temperature (Ts) of the leathers were tested. As the same time, it was attempted that the differences of Ts were explained from the point of view of molecular size. It was found that the Ts of no. 2, which increased with the increasing amount of no. 2 and eventually reached a fix quantify, was highest in these chrome-free tanning agents. As a result, leathers tanned by chrome-free tanning agents 1~#- 6~# exhibited perfect properties such as satisfactory fullness and softness, fine grain, light color and so on. Moreover, it was environment-friendly. It met requirements of shoe upper leather, clothing leather, case and bag leather. When the dosage of chrome was 2% under the optimized process condition , the Ts could be raised to 105°C and the leather possessed good handle. It had been fully reached standard of less-chrome tanning agent. The water-solubility and storable stability of chrome-free tanning agents 1~#- 6~# were very good, which achieved industrial...