Common technical problems of dyeing

The reasons for this are summarized as follows




1. Process formulation and operation




Develop unreasonable process or improper operation to produce colored flowers;




Unreasonable process (e.g., too fast temperature rise and fall)


Poor operation, knotting when dyeing, power failure when dyeing;


Heating too fast, heat preservation time is not enough;


Scouring water is not clean, uneven cloth PH value;


The content of oily slurry in the greying cloth is large, which has not been completely cleared after scouring.


Uniformity of cloth surface before treatment








Equipment problem




Such as disperse dye polyester after the heat setting machine oven temperature is not easy to produce color difference flower, rope dyeing machine pump force is not easy to cause color flower, etc.




The dyeing capacity is too large and too long;


Dyeing machine running speed is slow; Dye is boundless


The circulation system is blocked, the flow rate is too slow, the nozzle is not suitable and so on.








Raw material problem




Degree of uniformity of fabric and fiber material.




Dye problem




Dye easy to aggregate, solubility difference, compatibility poor, too sensitive to temperature, PH are easy to produce color flower and color difference. Such as active emerald green KN - R easy to produce color flowers.








Dyeing causes, including poor dye evenness, dye migration, dye fineness is too fine.








Water quality problems




Poor water quality, resulting in the dye and metal ions or dye and impurities condensation caused color flowers, color light color does not attach to the phenomenon.




Improper adjustment of dyeing bath PH value;




Auxiliary problem




Improper dosage of auxiliaries; For auxilary problem, the auxilary concerned with color flower mainly has penetrant, levelling agent, chelating dispersant, PH control agent and so on.








The solution to all kinds of colored flowers




(1) The color flower caused by uneven scouring.




Uneven scouring and removal of impurities on the fabric make the moisture absorption of the fabric different, resulting in colored flowers.




Measures:




1. The scouring agent should be quantitatively injected in batches, and the auxiliary agent should be balanced. Hydrogen peroxide injected at 60-70 degrees is more effective.






2. The heating time must be kept in strict accordance with the process requirements.






3. The dead cloth wrapping process should continue to keep heat for a short time.








(2) The scouring water stain is not clear, and the germplasm is stained with alkali, resulting in colored flowers.




Measures:




After washing water namely 10% glacial acetic acid in follow alkali hind to wash water again, make cloth surface PH7-7.5.




(3) the residual oxygen treatment of cloth surface after boiling is not clean.




Measures:




Now most of the deoxygenase additives are used to complete the deoxygenation treatment, the normal program quantitative injection of glacial acetic acid for 5 minutes, heating 50 degrees run for 5 minutes, with water quantitative injection of deoxygenase, heat preservation for 15 minutes, take water samples to measure the oxygen content.








(4) uneven chemical materials, dye solution is not enough to cause color flowers.




Measures:




First cold water stirring, then dissolve with warm water, according to the dye properties, adjust the temperature of the chemical, the temperature of the normal reactive dye chemical should not exceed 60 degrees, special dyes to cold water, such as Yanlan BR_V, can be taken separate material, must be sufficient stirring, dilution and filtration after use.








(5) Adding dye accelerant (yuan Ming powder or salt) too quickly.




Consequences:




Too fast will make the rope fabric surface with different dyeing agent, resulting in different dyeing rate, and the formation of color flowers.




Measures:




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


2. Batch adding should be less than the first time, more than the second time, each time adding 10-15 minutes apart, so as to promote dyeing evenly.








(6) The addition of fixing agent (alkali agent) too fast, too much, resulting in color flowers.




Measures:




1. Normal alkali-fall is injected in 3 times, with the principle of less before more. The first dosage is 1%10. The second time 3%10. The last 6%10.


2. Add slowly and evenly every time.


3. The heating speed should not be too fast, and the difference of the surface of the rope fabric results in the difference of the color absorption rate and the color. It is strictly required to control the heating rate (1-2 ℃/min) and adjust the vapor quantity on both sides.








(7) bath than too small, resulting in color difference color flowers.




Now many factories are air cylinder dyeing equipment,




Measures:




Master water quantity according to process requirement.








(viii) Soaping colored flowers.




After dyeing, the washing water is not clear. When soaping, the pH content is too high and the temperature is too fast, resulting in colored flowers. Heat up to the specified temperature must be kept for a certain time.




Measures:




The washing water is clean, and some factories are neutralized with acidic soap lotion. It should be run in the dyeing machine for about 10 minutes, and then heated up. If it is convenient for sensitive colors such as lake blue and color orchid, try to test the pH value before washing.


Of course, with the emergence of new soap lotion, there are low-temperature soap lotion in the market, another matter.








(9) The water in the dye bath is not clear, resulting in colored spots.




After soap washing, the residual liquid washing water is not clear, so that the residual liquid concentration inside and outside the fabric is not the same, when drying, fixed on the fabric to form color flowers.




Measures:




Wash thoroughly after dyeing to remove the floating color.








(10) Color difference (cylinder difference, strip difference) caused by color addition




1. Reasons for color difference:




A. The feeding speed is different. If the dose of promoting dyeing is small, whether to add in several times has an impact, such as one-time addition, the time is short, promoting dyeing is not enough, resulting in color.


B. Uneven rubbing on both sides of feeding will cause the difference, such as more dark on one side and less shallow on the other.


C. Holding time


D. Different color techniques caused by sample cutting lead to color difference. Requirements: the same method to cut the sample color.


For example: after 20 years of heat preservation, the sample is cut to match the color, and the washing degree is different after cutting the sample.


E. Different sizes of bath ratios cause color difference. Small bath ratio: dark bath ratio: light color


F. Different degree of post-processing. Sufficient aftertreatment, sufficient floating color removal, lighter than insufficient aftertreatment.


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


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








2. Add material and follow color.




1) Light color:




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. The color chasing dye must be fully dissolved and diluted, and used after filtration.


C. Color chasing corresponds to feeding at room temperature, and feeding corresponds to slow and even, so as to avoid excessive operation resulting in recolored flowers.




2) Dark color condition




A. Strengthen soaping and adequate post-treatment.


B. Add Na2CO3 for slight decolorization.