Study on removal of mordant agent from natural dyes printed fabric white ground with oxalic acid

In order to explore a method for removing mordant from natural dyes printed fabric white ground, the feasibility of removing Fe3 +mordant agent with oxalic acid as removing agent was investigated. The influence of oxalic acid on synthetic Long gum paste as thickener was evaluated by measuring the rheological properties. The effect of different factors, i. e. steaming temperature,humidity,time and concentration of oxalic acid,was studied by testing the whiteness and strength properties of silk fabric. The experimental results showed that oxalic acid had no effect on the rheological properties of synthetic Long gum paste. The optimum conditions for removal are: oxalic acid at a concentration of 0. 35%- 0. 40% of the weight of printing paste,steaming temperature of 100 ℃,humidity of 100%,and steaming time of 8 min.