In the polyester dyeing process, the heating rate, the holding temperature and the pH value of the dyeing bath have a greater impact on the dyeing quality. Theoretically, under the condition of ensuring that the fabric does not appear colored, the shorter the dyeing process, the lower the dyeing cost, but the higher the control requirements for the dyeing process. The dyeing process of dyeing fibers with a large amount of dyes (generally 30% to 90% dyeing) will be reduced due to the acceleration of the fabric speed, and poor control can easily produce color stains. In the heat preservation stage, the dye is easy to level dye on the fiber, and this period of time will not be shortened due to the acceleration of the cloth speed in the dyeing vat. When cooling down, the cooling rate should be slow, otherwise the polyester will shrink sharply and easily cause creases. Therefore, to control the rationalization of the dyeing process, the key lies in the stage of dyeing a large number of dyes.
1. The influence of stage heating dyeing on dyeing intensity
At 80 ℃, the dyeing strength of E-type dyes has reached 49.degree. 99%; when it rises to 90 ℃, the intensity soars to 62. 77%. During this period of time, the dye absorption is relatively fast, and heat preservation measures must be taken to prevent the fabric from producing stains. In production practice, it can be kept at 85 ℃ for 10 min, and the temperature can be raised normally at other temperatures.
The dyeing strength of SE type dyes reaches 35 at 80 ℃. 28%, much less than 49% of E-type dyes. 99%; the temperature rises from 110 ℃ to 120 ℃, and the dyeing intensity is increased from 49.degree. 34% increased to 60. 87%. During this period of time, the dye absorption is relatively fast, and heat preservation measures must be taken to prevent the fabric from producing stains. During production, the temperature can be kept at 110 ℃ for 10 minutes, and the other temperatures can be raised normally.
The dyeing strength of S-type dyes at 80 ℃ is only 5. 74%, much less than 49% of E-type dyes. 35. 99% and SE type dyes. 28%; the temperature rises from 110 ℃ to 120 ℃, and the dyeing intensity is increased from 19. 82% increased to 34. 13%; the temperature rises from 120 ℃ to 130 ℃, and the dyeing intensity is increased from 34.degree. 13% increased to 53. 34%, the dye absorbs quickly during this period, and heat preservation measures are required. It can be kept at 110 ℃ and 120 ℃ each for 10 minutes, and the temperature can be raised normally at other temperatures.
2. The effect of stage heating and dyeing on shade
The E-type dye has been absorbed completely at a lower temperature, and it can be seen from the residual liquid dyeing sample that the dye has been completely absorbed at 100 ℃; samples are taken after incubation from 80 ℃ to 130 ℃ for 30 min, the color sample is basically from light to dark, indicating The compatibility of the three dyes is better.
The SE dyes begin to absorb completely at medium temperature, and it can be seen from the residual liquid sampling that they have been completely absorbed at 110 ℃; samples are taken after incubation from 80 ℃ to 130 ℃ for 30 min, the color samples are basically from light to dark, indicating that three SE-types The compatibility of dyes is better.
S-type dyes only absorb completely at higher temperatures. It can be seen from the residual liquid sampling that the dye is almost completely absorbed after the temperature is raised to 130 ℃ and the temperature is kept for 10 min. After sampling from 80 ℃ to 130 ℃ for 30 min, the color of the color sample is basically from light gray to dark gray, indicating that the compatibility of the three S-type dyes is better.
When choosing dye combinations, try to choose the same type of dyes and avoid cross-level combinations, such as the combination of E-type dyes and S-type dyes, otherwise the chances of coloring will be very high.
3. The influence of different dyeing process curves on fabric shade
Different holding temperatures have little effect on the color of the dyed sample, and the color difference values are all within a reasonable error range. It can be seen that the use of a suitable heating rate and heat preservation point can greatly reduce the possibility of discoloration. In addition, control the cloth speed in the tank and the dye uptake rate so that the dye uptakes at a uniform speed, which can also effectively avoid the occurrence of colored flowers.