When the fabric dyed with disperse dye is cooled in the dyeing vat and sampled and matched with the standard color sample, if the dyed fabric is washed and treated, the color tone is slightly different from that of the standard sample, color correction can be used Homework to be corrected. When the hue difference is large, peeling and re-staining must be considered

Color repair
For fabrics with slight chromatic aberration, the following methods can be used: When the exhaustion rate is reduced and a large amount of dye remains in the residual liquid, it can be adjusted by extending the dyeing time or increasing the dyeing temperature. When the dyeing depth is slightly higher, this color difference can also be corrected by adding surfactants and leveling.

1.1 Methods of color repair
Before correcting the shade, you must have a full understanding of the color of the dyed fabric and the nature of the dye solution. The following methods can be used to modify the color:
(1) There is no need to remove the dyed object from the dyeing vat, just cool the dye solution to 50~70℃, and add the dye for color correction that has been prepared properly;
Then heat up for dyeing.
(2) The dyed fabric is unloaded from the dyeing machine, and then thrown into another dyeing machine, and then the dyeing process is performed by the boiling dyeing method and the guiding dyeing method.

1.2 The properties of color correction dyes
It is recommended that the dyes used for color repair have the following properties: (1) The dyes will not be affected by surfactants and become slow dyeing. When the color correction operation is carried out, a large amount of anionic surfactant contained in the dye remains in the dye liquor, and a small amount of the color correction dye will form a slow-dyeing effect due to the presence of the surfactant. Therefore, dyes for color repair must be selected that are not easily affected by surfactants and have slow-dyeing effects.
(2) Stable dyes that are not easily affected by hydrolysis and reductive decomposition. Dyes for color repair, when used in very light-toned color repairs, the dye is easily hydrolyzed or decomposed by reduction. Therefore, dyes that are not affected by these factors must be selected.
(3) Dyes with good levelling properties. Must have good level dyeing ability to obtain level dyeing effect.
(4) Dyes with excellent light fastness. The amount of dyes used for color correction is usually very small. Therefore, its sublimation fastness and wet fastness are very important, but not as urgent as the light fastness. Generally, the dyes used for color repair are selected from the dyes used in the original dyeing formula. However, these dyes sometimes do not meet the above conditions. In this case, it is recommended to choose the following suitable for color repair
dye:
C.I. (Dye Index): Disperse Yellow 46; Disperse Red 06; Disperse Red 146; Disperse Violet 25; Disperse Violet 23; Disperse Blue 56.

Peeling and re-staining

When the hue of the dyed fabric is different from the standard sample, and it cannot be corrected by color trimming or level dyeing, it must be stripped and re-dyed. Poly-cool fiber has a high crystalline structure. So it is impossible to use general methods to completely peel off the color. However, a certain degree of peeling can be achieved, and it does not need to be completely peeled when re-dyeing and repairing the color.

2.1 Part of stripping agent
This stripping method uses the retarding power of surfactants to strip the color. Although the stripping effect is quite small, it will not decompose the dye or damage the feel of the dyed fabric. The usual stripping conditions are: auxiliary: nonionic surfactant ten anionic surfactant 2~4L, temperature : 130℃, Q: 30~60min. See Table 1 for dye stripping performance.

2.2 Restore peeling
This peeling method is to heat the dyed fabric in the heat conduction margin to peel off the color, and then use a reducing agent to destroy the decomposed dye, and separate the decomposed dye molecules from the fiber fabric as much as possible. Its peeling effect is better than partial peeling method. However, there are still many problems with this peeling method. Such as the reattachment of the damaged and decomposed dye molecules; the color after peeling off will be very different from the original color. The hand feel and heavy dyeability of the dyed fabric will change; the dye holes on the fiber will decrease, etc.
Therefore, the reduction stripping method is only used when the previous partial stripping cannot be satisfactorily corrected. The color reduction process recipe is as follows:
Dye guide agent (mostly emulsion type) 4g/L
Non (anionic) ionic surface active agent 2g/L
Caustic soda (35%) 4ml/L
Insurance powder (or Dekuling) 4g/L
Temperature 97~100℃
Time 30min

2.3 Oxidation peeling method
This stripping method uses oxidation to decompose the dye to strip it, and it has a better stripping effect than the reduction stripping method. The oxidation stripping process prescription is as follows:
Dye guide agent (mostly emulsion type) 4g/L
Formic acid (formic acid) 2ml/L
Sodium chlorite (NaCLO2) 23g/L
Chlorine stabilizer 2g/L
Temperature 97~100℃
Time 30min

2.4 heavy staining
Commonly used dyeing methods can be used to re-dye the stripped fabric, but the dyeability of the dyed fabric must still be tested initially, that is, the sample room sample dyeing work must be done. Because its dyeing performance may be larger than that before peeling.

Summarize

When more effective color peeling is required, the fabric can be oxidized and peeled first, and then reduction peeling. Because reduction and oxidation peeling will cause the dyed fabric to crimp, which will cause the fabric to feel rough and hard, it must be considered comprehensively in the actual production process, especially the peeling of the different dyes illustrated in Table 1. Color performance. Under the premise that the color matching can reach the standard color sample, a more gentle repair method is generally used. Only in this way can the fiber structure be not damaged, and the tearing strength of the fabric will not drop greatly.