The causes of color flower are as follows

1. Improper selection of dyes

Dyeing acrylic fiber is different from dyeing other fibers. If the dyes are not selected properly, it is difficult to achieve leveling effect even by adding more leveling agents or improving dyeing conditions. Therefore, cationic dyes should be selected with the same compatibility value, and the compatibility value difference in the formula should be less than 0.5.

2. Improper selection and dosage of leveling agent

(1) leveling agents for acrylic fiber can be divided into two categories: slow dyeing leveling agents and transfer dyeing leveling agents

a. The principle of slow dyeing and leveling agent is as follows: in dyeing, the slow dyeing agent takes the first place in the dyeing seat. With the gradual increase of temperature, the slow dyeing agent is replaced by the dye and combined with the fiber to achieve the purpose of leveling.

Precautions for using retarder:

① If the dosage is small, the leveling effect is not good, and it is easy to make colored flowers. If the dosage is too much, it will also cause color.

② The key dyeing temperature of most acrylic fibers is about 90 ℃. If the dosage of pan is appropriate, the dyeing can be carried out at a uniform speed at 90 ℃ for 20 minutes. If it is too much, it will cause the dyeing temperature to rise and the dyeing speed to speed up, resulting in color.

③ Taking Zhuang Jie's cationic leveling agent zj-ch13 as an example, generally speaking, the dosage of dark color is 1g / L, and the dosage of light color is 0.2-0. 5g/l。

b. Transfer leveling agent: it has the properties of migration and transfer dyeing, and can transfer the dye from the place with deep color to the place with light color.

3. Differences in raw materials

The dyeing properties of acrylic fibers produced by various domestic companies are different. For example, the dyeing performance of Shanghai Jinshan Chemical Plant is fast, and that of Lanzhou Petrochemical is slow, which brings great difficulties to dyeing plants.

4. Improper control of temperature rise

Generally speaking, acrylic fiber starts to be colored from 80 ℃, and 87-92 ℃ is the key stage of coloring. During this period, the temperature must be raised slowly, and the speed is between 1 ℃ / 3 minutes and 1 ℃ / 6 minutes. It is best to keep temperature at 90 ℃ for 20 minutes

5. Change of pH value

When dyeing acrylic fiber, the pH value should be controlled between 3.5 and 5.5. When pH value is low, dyeing speed is slow, and it is not easy to dye flowers. But the pH value is too low and the color fastness is poor. When the pH value is high, the dyeing speed is fast and the color yield is high. But when the pH is too high, it is easy to dye flowers. If the pH is higher than 6, it may cause discoloration.

Generally speaking, the pH value of dyed acrylic fiber is about 4.5. In order to keep the pH value stable in the whole dyeing process, sodium acetate is added as pH buffer in the dyeing bath, so that the dyeing process does not change with pH fluctuation, and the leveling effect is achieved. Generally, the dosage of sodium acetate is 0.5g/l.

6. Impact on water quality

Soft water should be used for dyeing acrylic fiber, and the total hardness value is below 75ppm. If the hardness of water is high, it will cause dyeing. Some dyeing plants often appear the phenomenon of dyeing flowers, which may be caused by the high hardness of the water.

To sum up, dyeing acrylic fiber is better than dyeing other fibers. The difficulty is higher, and there are many factors to consider when making the process. How to develop an optimal dyeing process, it is suggested that the laboratory proofing for many times to determine the process.

normal atmospheric temperature

This heating process is a general dyeing process. Customers can make appropriate adjustment according to the types of dyed cloth and yarn. For example:

① The temperature of cloth with small gram weight is slower, and that of cloth with large gram weight is faster.

② The temperature rise of high count yarn should be slower, and that of low count yarn can be faster.

③ Dark color can heat up faster, light color can heat up slower

④ Dark color should be kept at 98 ℃ for a longer time, 45-60 minutes, but light color only needs to be kept at 98 ℃

Keep it warm for 15 minutes.