Preparation and assistant-dyeing of formaldehyde-free amphoteric acrylic retanning agent

Abstract With the enhancement of environmental protection consciousness, concerns have been raised about non-toxic and biodegradable leather retanning agents. According to European standard 2002/231/EC, free formaldehyde content products should be less than 150 mg/kg. As one agents in market, Multifunctional agent (MTA) is 372.22 mg/kg higher limit value. In this work, glutaraldehyde as an alternative was used modify acrylic polymer amphoteric prepared. Then it process, its assistant-dyeing properties were investigated. The results showed that modified with only 4.17 Meanwhile, presence amino groups improved dyeing by electrostatic attraction. Compared treated anionic agent, residual dye concentration effluent retanned decreased from 17.4 mg/L 10.0 mg/L, dyed had better resistances friction water-washing. addition, BOD 5 /COD value wastewater after Mannich base 0.32, indicating biodegradable. Moreover, good thermal stability, fullness physical mechanical properties. Graphical abstract