Improving The Dyeing Process Of Polyester/Cotton Blends By Disperse Dyes Microcapsules/Reactive Dyes In One Bath

Polyester/cotton blends possesses both function of moisture absorption ventilated on cellulose fibre and good type keeping and colorfastness on Polyester fibre, so it plays important role in all kinds of costume material. General polyester/cotton blends disperse/reactive dyeing are two-bath, one-bath-two-step and one-bath-one-step dyeing. These dyeing processes consume long time and need reduction clearing, causing low production efficiency and greatly consume of water, power, and steam. The more pivotal point is that reduction clearing would damage reactive dye. The chroma of dyeing wastewater is very deep and difficult to treat due to slather of auxiliaries.The dyeing process of polyester using microencapsulated disperse dyes in the absence of auxiliaries is exploited recent years. Its controlled-release and isolation properties to control the rate of dyeing were used to achieve the purpose of level dyeing and avoid staining fabric. Controlled-release and isolation properties of microencapsulated disperse dyes replace absolutely necessarily dispersing and penetrating agent in the dyeing of disperse dyes. The process not only save the auxiliaries, but also avoid pollution of chroma and burthen of COD, BOD as a result of auxiliaries radically. Since no auxiliaries are involved, the dyeing wastewater can be reused after filtration.In this paper, Microcapsules with a double-layered shell containing disperse dyes were prepared by means of in-situ polymerization. Dye microcapsules in different size were prepared with different system regulator PDA and different emulsion time. The size and distribution of microcapsules were tested by Laser Granularity Analyzer and the surface topography of them was observed by Scan Electron Microscope. Polyester/cotton blends were dyed by infrared high temperature high pressure dyeing machine. The effects of dyeing with disperse dyes microcapsules/reactive dyes dyeing process in one bath were tested by datacolor, soaping and dry/wet rub machine. The tests results show that the dyes microcapsules prepared by PDA whose dosage from 2% to 16% are easy to sieve and appear powder state after drying. The size range of the mean and median value are from 4 to 12μm, and emulsion time has little influence on them. The disperse dyes microcapsules prepared by 8% PDA with 10min emulsion behaves better in dyeing process of polyester without dispersant, level dyeing reagent and reduction clearing. And it is chose to carry out the next research of one bath dyeing process of polyester/cotton blends.Combined the advantages of the general disperse/reactive dyes one-bath dyeing of polyester/cotton blends and the polyester dyeing with disperse dyes microcapsules under high temperature high pressure condition without auxiliary reagent, both disperse dyes microcapsules and Argazol NF reactive dye were used to dye polyester/cotton blends in one-bath under different conditions. The optimum dyeing parameters were established by investigating of the bath ratio, dyeing temperature and heat preservation time. The results show that the dyed blends possess higher K/S value and better level dyeing at bath ratio 1:20. The process of dyeing should preserve heat properly at 80℃, and debase the speed of rise temperature controlling dyeing rate of reactive dye to implement level dyeing. At 130℃, preserve temperature for 30min. Then insulate disperse dyes microcapsules, continue to dye for 20min, then high quality color fastness fabric can be obtained.Finally, compared with the traditional dyeing process, results show that the new dyeing technology of disperse dyes microcapsules/reactive dyes in one bath dyeing process without dispersant, level dyeing reagent and reduction clearing can impart the polyester/cotton blends deeper color and excellent color fastness: dry/wet rub fastness, staining fastness and colour fading grade at 60℃are more than 4 grade. The chroma of dyeing wastewater is reduced obviously after filtrating microcapsules. And the dyeing waste water absorbency is about half of the absorbency of general dyeing process.In the interest of ensuring quality of product and not adding special device, above mentioned new dyeing process of polyester/cotton blends by disperse dyes microcapsules/reactive dyes in one-bath would greatly reduce trouble and save cost during dyeing polyester/cotton blends process. This new process not only save water and power, but also control the wastewater at beginning.