Be sure to understand the 10 key issues in reactive dye dyeing operations
1Why do you need to use it first when applying materials? When mixing a small amount of cold water, the mixing temperature cannot be too high?
First use a small amount of cold water to make the slurry to make the dye easily fully wet. If you pour the dye directly into the water, the outer layer of the dye will form a gel, which will wrap the dye particles and make the inside of the dye particles It is difficult to get wet and difficult to dissolve, so you should first mix the paste with a small amount of cold water, and then use hot water to dissolve it.
If the temperature of the chemical material is too high, it will cause hydrolysis of the dye and reduce the dye fixation rate.
2Why should you add materials slowly and evenly?
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 darker and the inner layer lighter, which may easily cause stains or streaks.
3Why does it take a certain period of time (such as: 10min) after adding the dye? Start adding salt at the rear?
Salt is a dye accelerator. When the dye reaches a certain level, it has reached saturation and it is difficult to continue dyeing. Salt is added to break this balance, but it takes 10 seconds before adding salt to promote dyeing. – Wait for about 15 minutes so that the dye can fully penetrate evenly, otherwise it will easily cause stripes and color flowers.
4Why should salt be added in batches?
The purpose of adding salt in stages is to promote dyeing evenly, so as not to promote dyeing too quickly and cause color blooming.
5Why does it take a certain period of time (such as 20 minutes) to solidify after adding salt? Color.
There are two main reasons: A. to allow the salt to dissolve evenly in the tank to fully promote dyeing; B. to allow the dyeing to be saturated and reach equilibrium before adding alkali to fix the color to achieve high dye uptake.
6Why does adding alkali become “fixed color”?
Reactive dyes Adding salt can only promote dyeing, but adding alkali will stimulate the activity of reactive dyes, causing the dye and fiber to react under alkaline conditions (chemical reaction) As a result, the dye is fixed on the fiber, so it is called “fixation” because of the chemical reaction that occurs in this fixation, achieving higher fastness. Once solidified, the color print will be difficult to achieve evenly.
7Why should the alkali be added in stages?
The purpose of adding it in stages is to make the color solid evenly and prevent color blooming.
If added at one time, it will easily cause excessive concentration of the local residual liquid and accelerate the reaction with the fiber, which will easily cause color blooming.
8Why must the steam be turned off first when adding materials?
(1) The purpose of turning off the steam before adding ingredients is to reduce the stripe difference and prevent color blooming.
(2) When the temperature on both sides of the controlled cylinder rises above 3°C, dyeing will be affected. Stripes will appear when the temperature exceeds 5°C, and the temperature will stop when the temperature exceeds 10°C
(3) The machine is undergoing maintenance.
(4) Someone has tested that the temperature in the cylinder is basically uniform before and after the cylinder is turned for 10-15 minutes after steaming, and is equal to the surface temperature, so when adding materials, H202 is added regardless of chlorine.When dyeing, you should turn off the steam before adding dyes, salts, and soda ash.
9Why ensure the process holding time after adding alkali?
The holding time should be calculated after the alkali is added and the temperature rises to the process holding temperature. Only when the panels are cut according to the process holding time can the quality be guaranteed, because the holding time is set according to a certain The laboratory that determines the amount of dye required for the reaction is also sampled at this time.
10Several kinds of shearing that do not follow the process regulations cause unstable quality.
(1) The time is not up to “correct” color clipping.
Due to plate making problems, material weighing problems, cloth weight and liquor ratio, etc., problems will cause color deviations. If the color has not been “corrected” before the time is up, this abnormality should be reported to the squad leader or craftsman. , no matter what, if the process and holding time are shortened, the dye reaction will not be sufficient, the color will not change, the color will be uneven, there will be no fullness, and the fastness will also be a problem.
(2) The board is cut early and the replenishment is inaccurate.
Dyeing can only be stable when the process heat preservation time is reached. The earlier the shearing time, the greater the change and the more unstable. If the time is not up for shearing, (after boiling, scouring, and washing , blow dry and give it to the craftsman for color inspection. Between the time of placing the order and weighing the material, the actual heat preservation time of the vat cloth has been extended. At this time, the dyeing has also increased. The vat cloth is too dark after adding supplementary materials. It has faded again.)
(3) There is no benefit in extending the time for cutting.
After the insulator is sheared, the dye reaction has ended, and it is useless to dye again. Instead, some of the dye that has been dyed will be re-hydrolyzed.
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AAANHGMKJLOI87
Disclaimer:
Disclaimer: Some of the texts, pictures, audios, and videos of some articles published on this site are from the Internet and do not represent the views of this site. The copyrights belong to the original authors. If you find that the information reproduced on this website infringes upon your rights, please contact us and we will change or delete it as soon as possible.
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