Study On Low-Temperature Dyeing Of Wool/Acrylic Blend

Traditional dyeing method of wool / acrylic blends was carried out by boiling dyeing. However, it usually brings on the fiber damage and dyeing defect, such as the loss of weight, deterioration of mechanical properties of wool, the difficulties of after-processing, rough touch, fabric yellowing and gray of color shade, and so on. Further more, it also had a negative impact and high energy consumption when the acrylic fibers were treated at high temperature for a long time. In order to prevent the dyeing rate too fast, lots of retarding agents which reduced the color yield should be added. Therefore, it is necessary to study the low temperature dyeing techniques of wool / acrylic blends. At present, low temperature dyeing of wool had being put in practice by some factories. However, there are still problems of the levelness, penetration and color fastness. However at present, there appears to be little information in the literature about the low temperature dyeing techniques of acrylic.The main purpose of this paper is to solve two major problems. The first problem is low dye uptake of acrylic fiber at 80~85℃. Secondly, we need to study the problem of poor leveling, penetration and color fastness at low temperature dyeing for wool, thus to accomplish low temperature dyeing technology of wool / acrylic blends.Firstly, the plasticizers (benzyl alcohol and butyl acetate) that could obviously improve the dye-uptake of cationic dyes were selected, and the best emulsifier (You Li Ru) that was used to prepare the acrylic low temperature dyeing accelerant was determined. Then the best preparation process of acrylic low temperature dyeing accelerant was develop: butyl acetate dosage 20% (the volume content compare to emulsion), emulsifier speed 10000rpm, emulsifier 1.76% (the volume content compare to emulsion), water dosage 78.24% (the volume content compare to emulsion), emulsification time 10min.The effects of the dyeing temperature, dyeing time and low temperature dyeing agent dosage on dye-uptake of cationic dyes were studied. Based on different low temperature dyeing agents, the two sets of acrylic low-temperature dyeing were developed. One of dyeing process was dyeing temperature 80℃, dyeing time 60min, dye bath pH value 4~5, the dosage of benzene alcohol 8mL/L, bath ratio 1:50. The another dyeing process was dyeing temperature 85℃, dyeing time 60min, dye bath pH value 4~5, the dosage of accelerant (butyl acetate as the active ingredient) 30mL/L, bath ratio 1:50. After dyeing using previous low temperature dyeing techniques, the shade of dyed fabrics remained unchanged, the color fastness to washing up to 4~5 grade, the fastness to rubbing is not less than 4 grade. Both could reach the grade of that of traditional dyeing. And the strength of dyed acrylic yarn had been obviously improved than that of conventional dyeing.By using optical OM, XRD, TG, DTG and other methods, the results showed that benzyl alcohol and self-made accelerant had significantly swelling effect to acrylic fibers. Meanwhile, the quasi-crystalline of acrylic both had also decreased. But its arrangement state of hyper molecular structure did not change. The thermal stability of acrylic fibers had a little change after treated by low temperature dyeing agent. But the extent of the effect was less than that of conventional dyeing.The study on dyeing kinetics showed that both benzyl alcohol and the seft-made accelerant could improve equilibrium adsorption capacity, dyeing rate constant, diffusion coeddicient, and decrease the half-dyeing time when cationic coroba blue X-GB was dyed in acrylic fiber at 80℃and 85℃. When the low temperature dyeing agents were used for the dyeing at 80℃and 85℃, the dyeing rate constant and diffusion coeddicient were far lower than that of conventional dyeing. Meanwhile, the half-dyeing time was obviously longer than that of conventional dyeing. So it could improve the level dyeing property of acrylic fabric.Aimed at the problems of wool low temperature dyeing, some dyestuffs that were suitable for low temperature dyeing of wool were selected in this paper, including Lanaset Yellow 2R, Lanaset Red G, Lanaset Gray G, Lanaset Blue 2R, Lanaset Bordeaux B, Lanaset Red 2B. Then according to migration, penetration, color fastness, and dye-uptake of dyestuffs at low-temperature dyeing, appropriate agent RS-80 was selected to improve dyeing property of wool in this paper. Except for the dye-uptake of Lanaset dyes is reduced little when using RS-80 , other kinds of dyeing properties could achieve that of the conventional dyeing.By studying on one-bath low temperature dyeing of wool / acrylic blends, the result show that the effect of low-temperature leveling agent RS-80 on dye-uptake and K/S value of acrylic is little. Both benzyl alcohol and dyeing accelerant could promote the dye-uptake and K/S value of Lanaset dyes. And the promotion of self-made accelerant is higher than that of benzyl alcohol. The agents in the one-bath of wool / acrylic blend in the low-temperature dyeing had good compatibility. Therefore, wool low-temperature leveling agent RS-80, benzyl alcohol and self-made accelerant could be applied to one-bath low-temperature dyeing of wool / acrylic blend products. So the dyeing recipe and dyeing process of wool / acrylic blends one-bath low temperature dyeing are developed.