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When the reactive dye is dyed, the dye can be directly dyed onto the cloth, and because of its good diffusion ability, the dye is easily diffused into the fiber, but since it has not yet chemically reacted with the fiber, it is easy to use water to treat most of the dye. Washed off, so the alkali agent must be used to promote the chemical reaction between the dye and the fiber to fix the dye on the fiber.

The former is called dyeing and the latter is called fixing.

Basic process:

1. Sorption (color absorption): The dye is absorbed into the fiber dyeing solution and diffused into the fiber.

2. Fixation (fixation) : The dye reacts with the fiber to form a covalent bond.

3. Washing (soaping): The unfixed dye is washed from the fiber. When dyeing, the reactive dye is first dissolved in water, and the dye and water molecules enter the inside of the fiber at the same time and are absorbed by the fiber.

Dye problem

The main problem may be that the dye is not completely opened during the feeding, and is directly added into the cylinder, resulting in the occurrence of the material point. (It is better to pre-form the dye and then add the auxiliary cylinder. The light color is preferably filtered once and then filtered. If the material is directly in the auxiliary tank, it is generally best to use hot water to make it, which may cause some dyes to hydrolyze faster, but the overall effect is not obvious. It is best to add the dyeing tank after ensuring that the dye is completely opened. It is also possible to consider whether the quality of the dye itself is the problem, so that the dye should be directly checked before entering the warehouse.

2. Electrolyte problems

Yuanming powder has not been added, although this effect may not be common, but if Yuanming powder is not opened (some individual manufacturers produce too much impurities in Yuanming powder, it is not easy to open), if it is not completely in dyeing If it is opened, the Yuanming powder will cause the cloth to appear stains during the dyeing process. (In this case, it is better to use the higher temperature water to make the Yuanming powder. Generally, some water is added to the auxiliary cylinder in the auxiliary cylinder. Open the steam after the powder, so the effect will be better.)

3. Alkali agent problem

The dyeing of reactive dyes generally uses soda ash as a fixing agent. The fixation of soda ash is slower than that of caustic soda, but its alkalinity is directly released, and the initial dyeing rate is relatively high, so if the control is started when the alkali is added in the process of adding alkali, It is possible to have a color flower phenomenon, especially the dyeing of sensitive colors and green color macromolecular dyes.

4. Water quality issues

Too high a hardness of the water used for dyeing may cause the dye to aggregate and appear a color point. This requires the dyeing plant to regularly check the water quality used. If the water hardness is high, it can be controlled by adding 0.2-1 g/L chelating dispersant during the dyeing process. The chelating dispersing agent not only has the chelating property to metal ions, but also has the functions of dispersing, scouring and increasing whiteness, and also has a blocking effect on metal ions, and is suitable for pretreatment, dyeing, post-treatment and other processes. It can adapt to the compatibility of various additives and can effectively prevent the re-adhesion of silicon spot oil or other pollutants. When used in dyeing, it has a certain leveling and retarding effect.

The scouring is uneven and the impurities on the fabric are not uniformly removed, so that the moisture absorption rate of the fabric is different, and the color flower is produced.

Measures:

1. The scouring aid is injected in batches, and the additives should be finished. Hydrogen peroxide is better at 60-70 degrees.

2. The tempering and holding time must be kept in strict accordance with the process requirements.

3. The dead cloth is wrapped and the cloth is to be kept warm for a while.

The water stains in the scouring are unclear, and the dyeing of the fabric with alkali stains causes the color flowers. After the cloth is cooked, the residual oxygen treatment on the cloth surface is not clean.

Measures:

1. After washing the water, 10% glacial acetic acid followed by residual alkali and then wash the water to make the cloth surface PH7-7.5.

2. Deoxygenation treatment was carried out with deoxygenase auxiliary agent. The normal procedure was quantitatively injected into glacial acetic acid for 5 minutes, and the temperature was raised at 50 degrees for 5 minutes. The deoxygenase was injected with water quantitatively for 15 minutes, and the water sample was taken to measure oxygen.

3. Uneven material, insufficient dye dissolution

Uneven materials, dye dissolution is not enough to cause color flowers.

Measures:

First, stir in cold water, then dissolve in warm water. Adjust the temperature of the chemical according to the properties of the dye. The temperature of the normal reactive dye material should not exceed 60 degrees. The special dye should be cold water, such as Yanlan br_v, which can be used separately. Stir, dilute and filter.

4. The dyeing agent (Yuanming powder or salt) is added too fast.

as a result of:

Too fast will cause the dyeing agent in the surface of the rope fabric, the concentration is not the same, resulting in different dyeing rates in the surface, and the formation of color flowers.

Measures:

1. The dye should be added in batches, and each addition should be slow and uniform.

2. The batch addition should be less before and after, and then added more than 10-15 minutes each time to make the dyeing uniform.

The fixing agent (alkaline agent) is added too fast and too much to cause coloration.

Measures:

1. The normal drop of alkali is divided into three quantitative injections, the principle of first less and then more, the first dose is 1% 10. The second time is 3%10. Finally 6%10.

2. Each addition should be slow and even.

3. The heating rate should not be too fast, and the difference in the surface of the rope fabric causes the color absorption rate to be different and the color is different. It is strictly required to control the heating rate (1~2 °C/min) to adjust the amount of vapor on both sides.

6. The bath ratio is too small, resulting in a color difference flower

Many factories are now air cylinder dyeing equipment, bath ratio 1:4 or even 1:3

Measures: Master the amount of water according to the process requirements.

7. Soap wash color flower

After washing, the water is not clear, the ph content is high when soaping, and the temperature rises too fast to cause color flowers. Keep warm for a certain period of time after warming up to the specified temperature.

Measures:

The washing water is clean, and some plants are neutralized with acidic soaping agent. It should be run in the dyeing machine for about 10 minutes, then heat up. If the sensitive color is such as lake blue, color orchid and other conditions are convenient, try to test the ph and then soap.

Of course, with the advent of new soaping agents, there are low-temperature soaping agents on the market.

8. The dye bath is not clear, causing color spots.

After the soaping, the residual liquid is not clear, and the concentration of the residual liquid in the surface of the fabric is different, and the color is fixed on the fabric during drying.

Measures:

After washing, wash the water thoroughly and remove the floating color.

9. Add color flowers

Color difference (cylinder difference, strip difference) caused by additive color

1. Reason for color difference:

A. The degree of feeding is not the same. If the dose of the dyeing is less, whether it is added in several times or not, such as one-time addition, the time is short, the dyeing is not sufficient, causing the color flower.

B. Feeding on both sides, the sputum is uneven, causing a difference, such as one side is darker and lesser than one side.

C, holding time

D, the coloring method does not cause the color difference.

Requirements: The same method is used to cut the color .

For example, after the insulation is 20, the color is cut, and the degree of washing after cutting is different.

E, the bath ratio is different, resulting in color difference. Small bath ratio: color depth and large bath ratio: light color

F, the degree of post-processing is not the same. The post-processing is sufficient, the floating color is removed sufficiently, and the color is less shallow than the post-processing.

G, on both sides, there is a temperature difference in the middle, causing a difference

Add color slowly, at least quantitatively for 20 minutes, and sensitive color for 30-40 minutes.

2. Add color to chase.

1) Light color status:

A. First check the original process prescription, and weigh the dye according to the degree of chromatic aberration and the weight of the fabric.

B. The second color-catching dye must be sufficiently dissolved, diluted sufficiently, and filtered.

C. The final color matching corresponds to feeding under normal temperature conditions, and the feeding is slow and uniform, so as to prevent the operation from being too urgent to cause re-coloring.

2) Color depth condition

A. Strengthen soaping and adequately handle.

B. Add Na2CO3 for slight decolorization.

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