| Polypropylene fiber（PP）is a kind of important synthetic fiber,it has the advantages of low density,high strength,good wear resistance,strong antibacterial,easy cleaning and other excellent characteristics.So,it has a wide application prospect in the field of textile and garment.PP fiber shows high hydrophobic as a synthetic fiber,and the suitable dyes for the coloration of PP is disperse dye.However,due to the lack of polar groups in PP polymer chain,the interaction force between PP and disperse dye is very weak,resulting in low dyeing exhaustion ratio and poor color fastness of disperse dye dyeing PP.In order to solve the"bottleneck"problem of PP fiber application,this paper designed and synthesized a series of disperse dyes containing sulfhydryl group structure,and studied on the dyeing and fixing conditions on the dyeing performance.We hope that this paper may provide theoretical and practical support for the development of special dyes and dyeing process for PP fiber.Five disperse dyes containing sulfhydryl group were synthesized by diazogen-coupling reaction and carbon-carbon coupling reaction.The D2S series D1,D2 and D3 dispersive dyes containing two sulfhydryl groups were synthesized by coupling reaction using p-aminophenylthiol,o-aminophenylthiol and m-aminophenylthiol as starting materials.D4 and D5 disperse dyes of D1S series were synthesized from diazo component of m-aminophenylthiol,N-methyl-N-hydroxyethyl aniline and N-phenyldiethanolamine by coupling component.Moreover,D6 disperse dye containing hydroxyl group replacing sulfhydryl group structure was also synthesized by coupling reaction with p-aminophenol as starting material for the comparative study with dyes containing sulfhydryl groups.The structure of the synthesized dyes was all characterized by 1H NMR and 13C NMR,and its UV-Vis spectral properties were studied.The dyeing properties of six disperse dyes on PP fabric were studied.Dyeing process was divided into two steps of exhausting dyeing step and oxidation fixation step,of which dyeing process used high temperature and high pressure method,oxidation fixation used hydrogen peroxide oxidation method.The effect of dyeing temperature,time,bath ratio and p H value on exhausting ratio were studied in exhausting dyeing step.The optimal conditions were determined as follows:dyeing temperature 110℃,dyeing time 40 min,dyeing bath p H 7.0,dyeing bath ratio1:20,chroma（amount of dye）2%（o.w.f）.Compared with hydroxyl dyes D6,exhaustion ratio of mercapto disperse dyes is about 70%,and the affinity of dimercapto dyes to fibers is higher than that of single mercapto dyes.The effect of hydrogen peroxide concentration,p H value and time on dye fixation were also studied by the comparision of K/S value of PP fabric before and after oxidation step.The mechanism of dye fixation was studied by organic solvent stripping experiment and infrared spectrum properties of dyed fabric.The results show that the optimal conditions of oxidation fixation are as follows:concentration of hydrogen peroxide is 20%,p H is 9 and fixation time is90 min.After oxidation fixation,the resistance to organic solvent stripping is greatly improved.IR spectra showed that the mercapto disperse dyes were cross-linked with each other by forming dye-S-S-dye bonds,which improved the affinity of dyes for PP fiber and showed very good dyeing fastness properties. |
