Study Of Application Of Teg On Natural Fiber Fabrics Printing With Reactive Dyes

The solubilization and moisture absorbency of urea play a critical role in the fixation of dyes and fibers when printed with reactive dyes. However, urea can break down into the compounds with N which may accelerate the growth of the algae material and ultimately causing the phenomenon of water eutrophication. Therefore, for the problem of environmental issues that world concern, the research of decreasing the amount of urea will become greatly meaningful.TEG was used as an alternative to replace urea in the paper, analyzing the performance difference between TEG and urea for the solubilization of the reactive dyes, moisture absorbency of silk and cotton fabrics and compatibility with the printing paste by testing the solubility of dyes, the capillary effect of fabrics, the diameter of fiber, the hold water value and PVI value of stock paste, the spreading value and stability of color paste. The results showed that the solubilization of TEG to reactive dyes such as red P-BN, reactive yellow P-6GS, reactive blue P-3R and reactive black P-GR was better than that of urea, the moisture absorbency of urea to silk and cotton fabrics was better than that of TEG; TEG was closed to urea in the influence on the stock paste, and having a good compatibility with the stock paste; the contour of printing pattern was quite clear and the stability of color paste was improved when using TEG, the compatibility between TEG and color paste was also good.Applying TEG to replace part of urea in silk and cotton fabrics printing with monochrome and combination, the effects of amount of TEG on the printing performance were studied through testing K/S values, color differences, permeability, rubbing fastness and washing fastness of printed fabrics. The results indicated that the best ratio of TEG to replace urea is 75% for silk and 30% for cotton, under which the prints can still maintain good permeability and dry rubbing fastness (≥4 grade), wet rubbing fastness and washing fastness can reach to full urea level (≥3-4 grade).The amount of ammonia was tested by Nessler's reagent colorimetric method to study the hydrolysis discipline of urea from the influence of temperature, time, pH value and initial concentration on decomposition of urea. Besides, the effects of TEG on the hydrolysis discipline of urea were studied. The results showed that the hydrolysis rate of urea was very slow and almost zero when the temperature was below 90℃, but it had a significant improvement and increase with the temperature rose as the temperature was above 90℃. The hydrolysis of urea was linear with time, what is said that it was one-level reaction. The hydrolysis rate of urea increased as the pH value decreased, and it declined obviously as pH value was 7~8, but less obviously as was above 8. The amount of ammonia that urea hydrolyzed was linear with the concentration of urea. Moreover, TEG has little effect on the decomposition of urea.