The Structure Of Reactive Dyes Effect On Electrochemical Salt-free Dyeing

Electrochemical dyeing technology of reactive dyes could complete free-salt dyeing, and it has become the research hot spot. Three types of reactive dyes(Reactive Yellow KN-GR, Reactive Yellow K-6G and Reactive Red M-2B) in this topic were selected to investigate dyeing under the electrochemical system.Active groups are difference in three kinds of reactive dyes. Control variable method was employed in the condition of electrochemical salt-free technology to discuss the optimum dyeing process. The K/S values of dyed cotton fabrics were tested. The results showed that the optimum dyeing process of the three types reactive dyes with electrochemical salt-free dyeing is, respectively, 0.4cm2 platinum electrode as anode area, the voltage of 7V, 6V and 5V,dyeing temperature of 30℃, 55℃ and 55℃, dyeing time of 40 min, 20 min and 20 min,fixation time of 40 min, 40 min and 50min; sodium carbonate concentration of 16g/L,16g/L and 12g/L.The preliminary exploration about electrochemical low-salt dyeing was also researched in experiments. The electrolyte sodium salt(nine kinds of single-salt and eight groups of mixed salts) were discussed to confirm the effects about reactive red KN-BS with electrochemical low-salt dyeing. The experimental results confirmed that the maximal K/S values(15.514 和 14.983) of dyed cotton fabric were using sodium sulfate(Na2SO4) and sodium tartrate(C4H4O6Na2) in single sodium salt as accelerating agent and that the maximal K/S value(15.816) of cotton dyed fabric is using mixed-salt sodium tartrate and sodium sulfate as accelerating agent; And the K/S value of dyed cotton fabric using mixed-salts as accelerating agent is superior to the single-salt. Electrochemical low-salt dyeing process as follows: 0.4cm2Pt/Pt-Ag/Ag Cl, the voltage of 8V, dyeing temperature of 30℃, dyeing temperature to 60℃ after 35min(1-2℃/min), adding sodium carbonate insulation 50 min for fixation,(C4H4O6Na2/Na2SO4=1:1) addition amount of 0.34 mol/L mixed salt.The influences which include basic structures from three kinds of reactive dyes were explored under electric-field. Configurating a certain concentration of dye solution,respectively, the absorption spectrum curve of dyeing solution from various stags were measured with UV-VIS absorption spectrophotometer. Contrast experiment from blank group(without fabric in traditional dyeing) and the control group(without fabric in the electrochemical dyeing) achieved that the electric-field(2~10V) did not destroy the basic structure from three kinds of reactive dyes under the electrochemical salt-free dyeing system.So it proved that the dyeing technology can be applied in the study of salt-free dyeing of reactive dyes.