Supercritical CO₂ Dyeing Technology And Fiber Characterization Of Properties On Villiform Fibers

The supercritical CO2 technology is a green processing technology.In recent years,it has been got widespread concern.In order to break through the supercritical CO2 dyeing technique lays a foundation on the difficulties in the dyeing process of wool and yak hair fibers and realize industrialization production,the dyeing process of wool and yak hair fibers in supercritical CO2 the wool and changes of fibers properties after dyeing is explored.Reactive disperse red G was adopted for supercritical CO2 technology research on the wool fiber.This paper optimized the factors affecting fiber dyeing effect by using the orthogonal experimental design method.Optimal modification process is:dyeing temperature 110?120 ?,dyeing time 70?90 min,dyeing pressure 24?26 MPa.Under these conditions,the short fibers content of dyed wool fibers was less than 30%,the breaking strength decreased less than 20%,the dyed wool fibers color fastness can reach 4?5 level,levelness reaches level 5.Reactive disperse blue R was adopted for supercritical CO2 technology research on the wool fibers.This paper optimized the factors affecting fiber dyeing effect by using the orthogonal experimental design method.The optimal modification process is:dyeing temperature 100?110?,dyeing time 60?80 min,dyeing pressure 23?25 MPa.Under these conditions,the short fibers content of yak hair fibers was less than 35%,the breaking strength decreased less than 25%,the dyed yak hair fibers color fastness can reach 4?5 level,levelness reaches level 5,color fastness and levelness were higher than level 4.Scanning electron microscopy(SEM),X-ray powder diffraction(WAXS),the Fu Liye transform infrared spectrometer(FT-IR),thermogravimetric analysis(TG-DTG)technology and other instruments and methods were used to investigate the changes of before and after the supercritical CO2 dyeing wool and yak hair fibers on the surface morphology and aggregation structure and chemical structure etc.Scanning electron microscopy(SEM)observation showed that the scales of dyed wool and yak hair fibers in supercritical CO2 were etched off,and that can help to improve the dyeing properties of the fibers.X-ray powder diffraction results showed that the crystallinity of wool and yak hair fibers dyed in supercritical CO2 was increased,amorphous and quasicrystalline phase crystal defect region was expanded.Fu Liye transform infrared spectroscopy(FT-IR)analysis showed that reactive disperse dyes can be combined to yak hair and wool fibers dyed in supercritical CO2,but also will cause the interaction between fiber molecule chain and functional changes.Thermogravimetric analysis(TG-DTG)showed that the heat decomposition stability of wool and yak hair fibers dyed in supercritical CO2 was improved.Scanning electron microscopy(SEM)and mechanical properties test results show that lower dyeing temperature and pressure release rates can effectively reduce the damage of fibers.In this paper,based on the characteristics of existing laboratory dyeing equipment,the supercritical CO2 dyeing heating system was optimized to design.The heat exchanger were put in the dyeing heating cycle to meet the needs of the dyeing temperature and ensure the fibers in dyeing kettle not affected by high temperature.The slowly step-up and step-down process in operation avoid the impact on fibers of supercritical CO2 fluid quickly,and this solves the wool and yak hair fibers damage technical problem of dyeing in supercritical CO2 fluid.