Elimination of color streaks in acrylic dyeing

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Elimination of color streaking phenomenon in acrylic dyeing

when acrylic fabric is dyed, when the number of anion separation friction reaches the set value, the automatic shutdown unit will use 1.5% (OWF), the dye retarder 1227 is 0.3% (OWF), and acetic acid will adjust the pH value of the dyeing bath to 4 ~ 4.5. The dyeing process adopts the stage heating method, that is, the temperature is gradually raised to 86 ℃ after feeding, and the dyeing is kept for 15min; Heat up to 100 ℃ and dye for 30min. Despite careful operation, the phenomenon of colored flowers still exists

first of all, various brands of acrylic fibers have their own saturation value (SF) with cationic dyes. For example, the saturation value of domestic acrylic fibers (Jinshan Petrochemical) is generally 2 3。 Therefore, the dye + retarder in the dyeing prescription should be about 2.5% with certain supersaturation. It has been proved that the effect of using surfactant 1227 as a retarding agent for the dyeing of acrylic fiber, which is particularly important in the market of plastic pelletizing machinery in China, is poor. There are generally three problems: ① too much surfactant will inhibit the dyeing of cationic dyes; ② Because of its strong cationic charge and strong affinity for acrylic fiber, it is very difficult to rework and repair; ③ If you add less, it is very easy to produce colored flowers. When dyeing with common cationic dyes, such as Brilliant Blue RL, adding 5 ~ 10g/l sodium sulfate (Na2SO4) can also improve the levelness. However, there is still a problem that acrylic fiber dyeing is easy to produce color streaks. The latest retarders mob and MOC introduced by Shanghai auxiliary factory are said to have two new properties, namely, affinity for acrylic fiber and cationic dyes. In this way, the conversion rate between the agent and the dye is stable in the dyeing process, which can not only avoid color blooming, but also prevent dye resistance. As long as the boiling time is well controlled, the color can be dyed, which is easy to operate. The amount of retarding agent is 0.5% ~ 1.5% (color from dark to light). However, it should be pointed out that sodium sulphate also has a retarding effect on cationic dyeing, and it is cheap and good

secondly, it is not necessary to adopt the stage method in the process. In terms of dyeing, it is generally suitable to add materials at room temperature and then heat up at the rate of 1.5 ℃/min, which drives the demand of the global engineering plastic market to 100 ℃, and heat preservation dyeing for 40 ~ 60min (the same as light to dark)

it must be pointed out that temperature fluctuation is forbidden between 80 ~ 100 ℃, especially at 100 ℃, otherwise ring dyeing will occur, which will affect dye exhaustion and reduce color fastness. Because the creep of acrylic macromolecular chain segment intensifies with the increase of temperature, it is very sensitive to temperature, that is, the creep changes with the change of temperature. This frequent change will make the combination of auxiliaries and dyes to the fiber loose (incomplete), and the replacement will be slow. Finally, the dye penetration cannot be achieved

finally, the cooling after dyeing should not be too rapid. The elasticity and bulkiness of acrylic fabrics will directly affect the style of finished products. Practice has proved that it is better to reduce the temperature from 100 ℃ to 60 ℃ at the speed of 1 ℃/min. To a certain extent, the disadvantages caused by too fast cooling are irreversible and can not be compensated by additives

in a word, acrylic fiber is a kind of acid-base resistant fiber, which is best dyed at one time. Because of dyeing defects, color stripping treatment must be carried out. In addition to detergent, alkali agent (Na2CO3) must be used for color stripping. After 100 ℃ × After 60min, wash it with water, neutralize it with HAC, and wash it with water. The quality of the finished product can not be compared with that of the first dyeing


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