Study On The Synthesis And Application Of Polyurethane-chromium(Ⅲ) Complexes Tanning Agent

In leather industry, the quality of leather by tanned chrome-tanning agent, which is better than other tanning agents. But the Cr (III) residue in the chrome tanning liquid waste will result in serious environment pollution. In addition, chromium resource in China is very limit, so the research of chrome-free and less-chrome tanning agent are very imperative. In this paper, polyurethane-chromium complexes tanning agent was synthesized, which were used to tan leather. The results showed that the shrinkage temperature of the tanned leather reached to 90°C, the increase ratio of thickness is 140% and the content chromium in waste water was much lower than the requirement of China National Industrial Effluents Standard, 10 mg/1. This invention provides us a new promising way to prepare less-chrome tanning agent.The chapter 1 is summarization. In this chapter, the tanning mechanism and latest research trend of the chrome-tanning agent were wholly summarized. A review with some references on composition, types, characteristic and interaction mechanism with skin collagen of polyurethane tanning agents, the trends of polyurethane resin tanning agents towards multifunctional product and its seriating will be attached importance to the future. Also the formation mechanism and application and research trend of the microemulsion were introduced. In addition, the environmental benign tanning agent technique was pointed out. In the last part of this chapter our design were presented, and synthesized polyurethane-chromium complexes tanning agent, in order to decreased environment pollution.The chapter 2, studying on the polyurethane ligands and their chromium complexes. Firstly, the pre-polymer based on tolylene diisocyanate (TDI) and tartaric acid (TA) was prepared, and then different average molecular weight of polyethylene glycols (PEG) as a chain extenders were added to the pre-polymer, and different molecular weight of the polyurethane ligands were obtained. Several factors that influence that the synthesis of the ligands such as raw materials dehydration, reaction...