When the acrylic fabric was dyed, the anionic dye amount was 1.5% (owf), the retarder 1227 was 0.3% (owf), and the acetic acid adjusted the bath pH to 4 to 4.5. The dyeing process adopts a phase warming method, that is, the temperature is gradually increased to 86° C. after the feeding, and the thermal insulation dyeing is performed for 15 minutes. The temperature is then raised to 100° C. and dyed for 30 minutes. Despite careful operation, there are still color phenomena.
First of all, all brands of acrylics, with cationic dye colors have their own saturation value (SF), such as domestic acrylic (Kingshan Petrochemical), the saturation value is generally 2.1-2.3. Therefore, the best dyeing agent in the dyeing prescription should be about 2.5% with a certain degree of supersaturation. Practice has proved that the use of surfactant 1227 for acrylic dyeing retarding agent is not effective, there are generally three problems: 1 plus more, to the cationic dye inhibition; 2 because the additives are particularly strong positive charge, Acrylic has a high affinity and it is very difficult to rework and repair; 3 less, and it is easy to produce color flowers. Normal type cationic dyes, such as Brilliant Blue RL dyeing, can also improve the leveling properties by adding 5 to 10 g/L of sodium sulfate (Na2SO4). In spite of this, there are still problems with the coloring of acrylic fibers. Shanghai Auxiliary Plant's newly introduced retarding agents, MOB and MOC, are said to have two novel properties, namely affinity for both acrylic and cationic dyes. In this way, the conversion rate of the tanning agent and the dyestuff during the dyeing process is stable, which can avoid the color flowers and prevent the dyeing. As long as the control of the boiling time can be dyed good color, easy to operate, slow dye dosage of 0.5% to 1.5% (from dark to light color). However, it is still necessary to point out that Yuan Mingfen also has a slow-dyeing effect on cationic dyeing, and it is also inexpensive.
Second, there is no need to adopt a stage method in the process. In terms of dyeing, it is generally advisable to feed at room temperature, then increase the temperature to 100°C at a rate of 1.5°C/min, and incubate and stain for 40 to 60 minutes (with light to dark colors).
It must be pointed out that between 80 and 100 °C, especially at 100 °C, avoid temperature fluctuations, otherwise ring dyeing will occur, affecting dye exhaustion and reducing color fastness. Because the peristaltic movement of the macromolecular segment of the acrylic fiber increases with increasing temperature, it is very sensitive to temperature, that is, the peristaltic motion changes with temperature. This frequent change will loosen (incompletely) the binding of the auxiliaries and dyes to the fibers, slow the replacement, and eventually fail to achieve penetration.
Finally, the cooling after dyeing can not be too rushed. The elasticity and bulkiness of acrylic fabrics will directly affect the finished product style. Practice has proved that it is best to reduce from 100°C to 60°C at a rate of 1°C/min. To a certain extent, the ills caused by cooling too quickly are irreversible and cannot be compensated with additives.
In short, acrylic is a kind of acid and alkali resistant fiber, and it is best dyed once. Because it is stained with rickets, it must be stripped. In addition to detergents, it must be supplemented with an alkali agent (Na2CO3), washed with water at 100°C for 60 minutes, neutralized with HAc, and washed. The quality of finished products cannot be compared with that of one-time dyeing.