Formaldehyde-free Dye T Stubbs Improve Discharge Stability And Efficiency Of Research

The traditional discharge agents in printing and dyeing industry are formaldehydehydrosulfite reducing agents and mainly include three shortcomings as following:(1) theyrelease free formaldehyde. Specially, residual discharge agents are hard to wash due to thefilming function of binder in pigment discharge printing.(2) they have many disadvantages suchas decomposition, large consumption, high cost and short storage life in paste mixture andstorage process.(3) they contains the (heavy) metal ion, which have bad effect on the stability ofthe synthetic thickener in pigment printing. Discharge agent T can overcome the above problemsof the traditional discharge agents. However, discharge agent T has a low solubility, and can notbe fully dissolved and homodisperse in the discharge paste, which inhibits the discharge agent Tfrom passing through screens, and weakens the reducing ability to ground dyes. In this paper, thehighly efficient and stable formaldehyde-free modified discharge agent T was prepared and theabove problems occurred in the traditional discharge agents were dissolved. Modified dischargeagent T improved the discharge effect and was developed in Pigment discharge printing processwhich meets the demands of the large industrialization production.In this paper, modified discharge agent T was prepared by grinding in aqueous andnon-aqueous medium. The whiteness of fabrics after white discharge was compared between thetraditional discharge agents and modified discharge agent T. The effect of grinding process anddispersing agent of modified discharging agent T on the particle size, surface morphologies andcrystal structure were studied by particle size analyzer, FESEM and XRD. The effect of thedispersion medium and the discharge stability of grinding modified discharging agent T wereanalyzed by whiteness, handle and electronic strength tests. In addition, the modified dischargeagent T was applied in pigment discharge printing. we also optimized the ground dyes, colourcoatings and steaming, and developed pigment discharge printing process for modified dischargeagent T.The results show that:(1) The whiteness index of wet grinding process for discharge agentT was better than the dry grinding, and the optimal conditions was chose as follows: grindingspeed was600rpm, the ratio of grinding medium and grinding the sample mass was3:1, theconcentration of discharge agent T was50%and grinding time was60min. The whiteness index of modified discharge agent T was better than the traditional discharge agent H, but less thanDccroline, but with littlte effect on the fabric handle and strength.(2) The particle size andagglomeration of discharge agent T by adding PVP and Tween-20dispersing agent in watermedium system could be reduced, so did si-10and oil acid dispersing agent for D5mediumsystem.(3) The modified discharge agent T prepared by grinding in D5and glycerol-ethanolmedium had good storage stability.(4) In pigment discharge printing process, the optimumsteaming process of the modified discharge agent T on silk and cotton fabric were: steamingtemperature was at105℃with102%humidity for8minutes for silk and10minutes for cotton.(5) DyStar Imperon series could be used as colour coatings for modified discharge agent T. Azoweak acid dyes and DyStar Remazol reactive dyes could be used as ground dye for modifieddischarge agent T.