An Investigation Into The Grafting Modification And The Dyeing With A Cationic Dye Of Cotton Fabric

Cotton fabric has good hygroscopicity moisturizing effect, without any stimulation contacting with the skin. So for humans, it is an ideal type of fabric. Along with the use of chemical fiber for many years, and the rising price of cotton fiber, the role of cotton fabric has changed from original low-end consumer products to high-end consumer goods in the consumer market. The requirements of people for fabrics now have also transformed from simply prevention of colds to the directions of individuation and functionalization. The cationic dye has the advantages of bright color, strong power of fixation. The dyeing of cotton fiber with cationic dyes can’t be reached currently. But if it’s true, it not only satisfies people’s demand for clothing, but also bring huge economic benefits. This is the purpose of this study.This paper is divided into two sections mainly:grafting modification of cotton fiber; the dyeing of modified cotton fiber. Grafting agent which was used for grafting, was provided by one of our cooperative partners. The influences of concentration of the grafting agent, dosage of alkali agent and sodium sulfate, grafting temperature, grafting time on grafting, were discussed and finally we found the best grafting process. Then on the basis of the first part, the dyeing process of the modified cotton fabric was studied. The second part includes three aspects, light color, neutral color and deep color. The influences of pH value, dyeing temperature, dyeing time, dosage of sodium sulfate, were analyzed, and got the ideal processes.Ideal process of modification:grafting agent76%(o.w.f), sodium carbonate40g/L, grafting temperature85℃, grafting time20min, dosage of sodium sulfate45g/L. Ideal process of dyeing:(1) light color:dyestuff concentration0.5%, pH7, dyeing temperature50℃, dyeing time30min, dosage of sodium sulfate10g;(2) neutral color:dyestuff concentration1.5%, pH7, dyeing temperature50℃, dyeing time30min, dosage of sodium sulfate10g;(3) deep color:dyestuff concentration2.5%, pH7, dyeing temperature50℃, dyeing time60min, dosage of sodium sulfate10g.Fastness and the strength of swatches,which were obtained respectively by the best processes of light color,neutral color and deep color, were studied finally. It was indicated that all of the fabric swatches have a bad wet rubbing fastness. This may relate to the weak binding force between the cationic dye with the modified cotton. The wet rubbing fastness can be improved of1-2grade by using proper fixing agents or cross-linking agents in the post-treatment. We also found that the strength of all swatches has decreased. Modification results in a local increase of stress, which may be the reason.