10 small questions about the key operations of reactive dyes. Do you understand?

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1Why do you need to use a small amount of cold water to adjust the pulp when the material is used, and the temperature of the material cannot be too high?

Firstly, the purpose of mixing with a small amount of cold water is to make the dye easily wetted thoroughly. If the dye is poured directly into the water, that is, the outer layer of the dye forms a gel, the dye particles are wrapped up so that the interior of the dye particles is difficult to be opened. Use a small amount of cold water to make a slurry and then use hot water to open it.

If the temperature of the material is too high, the dye will be hydrolyzed and the dye fixation rate will be reduced.

Why slow and even when adding 2 ?

This is mainly to prevent the dye from being stained too quickly. If the dye is quickly added at one time, the dyeing rate will be too fast, and the outer layer of the fiber will be deep, and the inside of the fiber will easily cause color flowers or stripes.

3 Why do you add salt after dyeing for a certain time (eg 10min) after adding the dye?

Salt is an accelerant. When the dye reaches a certain level, it has reached saturation. It is difficult to continue to add salt to break this balance, but it takes about 10 to 15 minutes before the salt to promote dyeing. Full penetration evenly, otherwise it is easy to cause strips and flowers.

4 Why add salt to graded?

The purpose of adding salt in order is to promote uniform dyeing, so as not to promote dyeing too fast, resulting in color flowers.

5 Why does it take a certain period of 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 uniformly in the cylinder, to fully promote B, to promote the dyeing to reach saturation after reaching the saturation, and then add alkali to fix the color to achieve the highest amount of dyeing.

6 Why does the addition of alkali become a "fixed color"?

The addition of salt to reactive dyes only promotes dyeing, but the addition of base will stimulate the activity of the reactive dyes, allowing the dyes to react with the fibers under alkaline conditions (chemical reaction), thus fixing the dyes on the fibers, so the “fixation” is also due to This kind of fixation undergoes a chemical reaction and achieves high fastness. Once solid color printing is difficult to uniform.

7 Why do you need to add the bases in batches?

The purpose of adding in order is to make the fixation uniform and prevent coloration.

If a one-time addition can cause local residual high concentration and fiber reaction to be accelerated, it can easily cause coloration.

8 Why must feed off steam?

(1) The purpose of shutting off the steam before feeding is to reduce the number of stripes and prevent coloration.

(2) When the cylinder temperature rises, the temperature on both sides exceeds 3°C. Dyeing has an effect. When the temperature exceeds 5°C, there are streaks, and the temperature exceeds 10°C.

(3) Machine maintenance.

(4) Some people tested that pulling the cylinder is 10-15 minutes after the steam is turned. The temperature inside and after the cylinder is basically uniform and equal to the temperature of the table. Therefore, no matter whether it is added to H202 or dyed with salt and soda, it is Steam should be added before filling.

9 Why do you ensure the process heat preservation time after adding alkali?

The holding time should be calculated from the end of the addition of alkali, and the temperature is only calculated when the temperature is raised to the process of holding the temperature. Only the shearing time of the holding time of the process can ensure the quality, because the holding time is determined according to the amount of time required for the dye to be determined. The laboratory is also proofing this time.

10 Several kinds of shearing plates that are not in accordance with the regulations have caused unstable quality.

(1) The time does not reach the "right" color shear plate.

Due to the problem of counting and weighing the material of the board, problems such as cloth weight and bath ratio will cause color deviation. If the time has not arrived, it should be reported to the supervisor or the technologist in case of abnormal color. Anyway, shorten the process and keep the time Dye reaction is not sufficient, the color dyeing is constant, uneven, there is no fullness, fastness is also a problem.

(2) Cutting off the board ahead of schedule, and feeding materials are inaccurate.

Dye uptake can only be achieved if the process is kept warm. The earlier the shearing time, the greater the change and the more unstable, if the time does not reach the shearing plate, (after boiling, training, washing, and drying to give the technicians a Until the time of billing, the actual holding time of the cylinder cloth has been extended. At this time, the dyeing has also increased. The addition of the cylinder cloth is too deep, and it will be re-lighted.)

(3) There is no benefit from extending the time to cut the board.

Exceeding the heat-insulating children as cutting plates, the dye reaction has ended, and the dyeing is no longer useful. Instead, some of the already dyed dyes are re-hydrolyzed.

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