10 Mistakes Often Made with Reactive Dyes!

Reactive Dyeing supplier shares this article for you.

1. Why is it necessary to adjust the slurry with a small amount of cold water when chemicalizing, and the temperature of chemical should not be too high?

(1) The purpose of adjusting the slurry with a small amount of cold water is to make the dye easy to fully penetrate. If the dye is poured directly into the water, the outer layer of the dye forms a gel, and the dye particles are wrapped, making the inside of the dye particles difficult to penetrate and difficult to dissolve. , So you should first adjust the slurry with a small amount of cold water, and then use hot water to dissolve it.

(2) If the temperature of the chemical is too high, it will cause hydrolysis of the dye and reduce the dye fixing rate.

2. Why should it be slow and even when feeding?

This is mainly to prevent the dye from being dyed too fast. If the dye is added quickly at one time, the dyeing rate will be too fast, which will make the outer layer of the fiber deep and the light inside easy to cause color flowers or streaks.

3. After adding the dye, why should it be dyed for a certain time (for example: 10min) before adding salt?

Salt is a dye accelerator. When the dye reaches a certain level, it is saturated and it is difficult to continue dyeing. Adding salt is to break this balance, but it takes about 10-15 minutes before the salt is added to promote dyeing. Fully penetrate evenly, otherwise it will easily cause streaks and color flowers.

4. Why add salt in batches?

The purpose of adding salt in stages is to promote the dyeing evenly, so as not to promote the dyeing too fast and cause color flowers.

5. Why it takes a certain time (such as 20 minutes) to fix the color after adding salt.

There are two main reasons: A. It is to make the salt dissolve evenly in the tank to fully promote the dyeing. B. To allow the dyeing to enter the dyeing saturation and reach equilibrium, then add alkali fixation to achieve the highest dyeing amount.

6. Why does adding alkali become "fixing color"?

The addition of salt to reactive dyes only promotes dyeing, but the addition of alkali will stimulate the activity of reactive dyes, causing the dyes and fibers to react (chemical reaction) under alkaline conditions to fix the dyes on the fibers, so "fixing" is also due to This type of color fixation takes place chemically and achieves high fastness. Once the solid color printing is difficult to uniform.

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7. Why should we add alkali in batches?

The purpose of adding in stages is to make the fixation uniform and prevent color flowering.

If it is added at one time, it may cause the local residual liquid to be too high in concentration and accelerate the reaction of the fiber, which will easily cause color flowers.

8. Why do I have to turn off the steam when feeding?

a. The purpose of shutting off steam before feeding is to reduce the difference and prevent the color flower.

b. When the temperature of the control cylinder is increased, the temperature on both sides exceeds 3°C. Dyeing has an effect. If the temperature exceeds 5°C, there will be streaks. If the temperature exceeds 10°C, the machine will stop for maintenance.

c. Someone has tested that the temperature of the cylinder is about 10-15 minutes after steaming, and the temperature in the cylinder is almost uniform and equal to the surface temperature. Turn off the steam before feeding.

9. Why ensure the process holding time after adding alkali?

The holding time should be calculated after adding the alkali and heating to the process holding temperature. The quality can only be guaranteed if the board is cut according to the process holding time, because the holding time is determined according to how much time is required for a certain amount of dye to react. The laboratory is also proofing at this time.

10. Several types of inconsistent quality caused by not cutting according to the process regulations.

The time is not up to the "right" color cutting board.

Due to the problem of material counting and weighing, the problem of fabric weight and bath ratio, etc., will cause color deviation. The abnormality of the color is not correct when the time is up. Report to the monitor or the technician. Anyway, shorten the process and keep warm time The dye reaction is not sufficient, the color is unchanged, the color is uneven, there is no fullness, and fastness is also a problem.

Cutting boards early, the feeding is not accurate.

Reactive dyeing's dyeing can only be stabilized when the process holding time is reached. The earlier the cutting time, the greater the change and the more unstable, if the time is not up to the cutting board, (after cooking, training, washing and drying, it will be sent to the technician. Color, the time of opening the billing and weighing, the actual insulation time of this cylinder cloth has been extended, and the dyeing has also increased at this time. The cylinder cloth is too deep when adding supplements, and it needs to be lightened again.)