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The cause of the color flower and how to solve it

Date:Oct 12, 2020

1. The reasons for the synthesis are:

1.1. Process formulation and operation issues:

Unreasonable formulation of the process or improper operation produces stigma;

Unreasonable process (such as rising and falling temperature too fast)

Poor operation, knotting during dyeing, and power outage during dyeing;

The temperature rises too fast and the heat preservation time is not enough;

The scouring water is not clean, and the pH value of the cloth surface is uneven;

The crude cloth contains a large amount of oily slurry, which has not been completely removed after scouring;

Uniformity of pre-treatment cloth surface


1.2. Equipment problems:

Equipment failure    

For example, after the disperse dye dyes polyester, the temperature in the oven of the heat setting machine is also easy to produce chromatic aberrations, and the insufficient pump power of the rope dyeing machine can easily cause chromatics.

The dyeing capacity is too large and too long;

The dyeing machine runs slowly; the dyer has no boundaries

The circulation system is blocked, the flow rate is too slow, the nozzle is not suitable, etc.


1.3. Raw material issues:

Fiber raw materials and fabric uniformity


1.4. Dye problems:

Dyes are easy to aggregate, have poor solubility, poor compatibility, and are too sensitive to temperature and pH, which are easy to produce color and color differences. For example, active turquoise blue KN-R is easy to produce color flowers.

The reasons for dyeing include poor levelness of dye, migration of dye during dyeing, and fineness of dye


1.5. Water quality issues:

Poor water quality may cause dyes and metal ions to combine or dyes and impurities to condense, causing color blurs, and light colors are not attached.

Improper adjustment of dye bath pH;


1.6. The problem of additives:

Improper dosage of additives; for the problem of additives, the additives related to color patterns mainly include penetrants, leveling agents, chelating dispersants, and pH control agents.


2. Solutions to various colors


(1) Uneven cooking results in discoloration.

The unevenness of scouring and the uneven removal of impurities on the fabric will cause the moisture absorption rate of the fabric to be different, resulting in colored flowers.


Measures:

1. The scouring additives are injected quantitatively in batches, and the additives should be all in place. The effect of injecting hydrogen peroxide at 60-70 degrees is better.

2. The cooking and holding time must be kept strictly in accordance with the process requirements.

3. The dead cloth wrapping treatment should continue to keep the heat for a break.


(2) The scouring water is unclear, and the fabric is stained with alkali dyeing.

Measures:

After washing the water, the residual alkali is mixed with 10% glacial acetic acid and then washed with water to make the cloth surface PH7-7.5.


(3) The residual oxygen treatment on the cloth surface is not clean after cooking.


Measures:

At present, most of the deoxygenase additives are used to complete the deaeration treatment. The normal procedure is to inject glacial acetic acid for 5 minutes, increase the temperature for 5 minutes, and inject the deoxygenase with water quantitatively, keep it for 15 minutes, and take a water sample to test oxygen.


(4) Uneven chemical materials and insufficient dissolution of dyes cause color blur.


Measures:

Stir in cold water first, then dissolve in warm water. Adjust the temperature of the chemical material according to the dye properties. The temperature of the normal reactive dye chemical material should not exceed 60 degrees. For special dyes, cold hydrate material, such as brilliant blue br_v, can be used as a separate chemical material, and it must be sufficient Stir, dilute and filter before use.


(5) The addition speed of the dye accelerator (sodium sulfate or table salt) is too fast.


as a result of:

Too fast will make the surface of the rope-like fabric have a dye accelerating agent, the concentration is different, resulting in different surface and inside accelerating rate, and the formation of colored flowers.


Measures:

1. The dye should be added in batches, and each time should be added slowly and evenly.

2. Adding in batches should be less in the first time and more in the later time. Each addition should be separated by 10-15 minutes to make the dyeing uniform.


(6) Fixing agent (alkali agent) is added too fast or too much, causing color blur.

Measures:

1. Normally drop the alkali into three quantitative injections, the principle of first being less and then more, the first dosage is 1% 10. The second time 3% 10. The last 6% 10.

2. Each addition should be slow and even.

3. The heating speed should not be too fast. The difference in the surface of the rope fabric will cause the color absorption rate to be different. It is strictly required to control the heating rate (1-2℃/min) to adjust the steam volume on both sides.


(7) The bath ratio is too small, causing chromatic aberration.

Many factories now have air cylinder dyeing equipment,


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


(8) Soaping colored flowers.

After dyeing, the washing water is not clear, the pH content is too high during soaping, and the temperature is too fast to cause color stains. After heating up to the specified temperature, keep it warm for a certain period of time.


Measures:

The washing water is clean, and some factories use acid soaping agent to neutralize. Run in the dyeing machine for about 10 minutes, and then heat up. If the conditions are convenient for sensitive colors such as lake blue and colorful blue, try to test the pH before soaping.

Of course, with the emergence of new soaping agents, there are low-temperature soaping agents on the market, which is another matter.


(9) Unclear water in the dye bath, causing color spots.


After soaping, the residual liquid washing water is not clear, and the concentration of the residual color liquid on the surface and the inside of the fabric is different, and it will be fixed on the fabric during drying to form colored flowers.


Measures:

After dyeing, wash with enough water to remove floating colors.


(10) Chromatic aberration caused by additive color (cylinder aberration, bar aberration)


1. Reasons for color difference:

A. The feeding speed is different. If the dose of the dye is added is small, it will affect whether it is added in batches, such as one-time addition, the time is short, and the dyeing is not sufficient, causing color blur.

B. The rubbing on both sides of the feed is uneven, causing strips, such as one side with more dark color and less side with lighter.

C. Holding time

D. Different color techniques of cut samples cause color difference. Requirement: Cut samples in the same way to match colors.

For example, the color of the cut sample after the heat preservation is 20, and the degree of washing after the cut sample is different.

E. The different size of bath ratio causes color difference. Small bath ratio: deep color Large bath ratio: light color

F. The degree of post-processing is different. Adequate post-processing, adequate removal of floating color, lighter color than insufficient post-processing.

G. There is a temperature difference between the two sides, resulting in a gap

Add color slowly, at least 20 minutes of quantitative injection, and 30-40 minutes for sensitive colors.


2. Adding materials to chase color.

1) Light color condition:

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

B. Chasing dyes must be fully dissolved, fully diluted, and used after filtering.

C. Chasing color corresponds to feeding under normal temperature conditions, and the feeding is slow and uniform to prevent re-coloring caused by excessive operation.

2) Color depth

A. Strengthen soaping and adequate post-treatment.

B. Add Na2CO3 for slight decolorization.


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emily@tiankunchemical.com

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