In actual production, it is impossible for the dyeing size to have no difference at all, and effective methods should be taken to correct it. The common solutions are briefly described as follows.
Cleaning method

1. Cold water cleaning

In cotton and its blended fabrics, after the cotton component is dyed with direct dyes or reactive dyes, floating or dull color appears. Generally, continue to wash with water, or add auxiliary water to wash in the water bath. If the water hardness is too high, 0.5-2g/L chelating dispersant can be added to improve it.

2. Wash with warm water

When the polyester blended fabric is dyed, there are many kinds of dyes and auxiliaries, which can be washed at 40°C to facilitate the dissolution of residues contaminated on the fabric. Cellulose fibers are dyed with direct blended dyes. If the overall color of the large sample is darker than that of the small sample, the color will be similar after washing with warm water, and the color fastness can be improved to a certain extent. To

3. Hot water cleaning

Hot water cleaning is mostly used for silk or synthetic fiber dyed with acid, direct and basic dyes and their interwoven fabrics. If the color is too dark, 1-20% of the dye needs to be removed, and it can be washed with hot water at 70-80℃. For silk fabrics in the hot water bath, add 0.3-0.5L of leveling agent (leveling agent); polyester, nylon and other synthetic fiber blended fabrics can be added with 0.5-1.0L of repair agent or dye carrier.

Due to the small amount of auxiliary added in the hot bath, the fabric only needs to be washed with running water to room temperature. If the dyed fabric is treated with cationic fixing agent and softener, it is best to add 2~4L dispersant DAM in the hot bath. Hot water washing (repair) is carried out on the original dyeing equipment in principle, such as nylon spinning, acetate fiber and its interwoven silk after dyeing, if the overflow machine (rope) hot water washing is used, the fabric will be permanently wrinkled. To

Additive addition method

1. Add electrolyte

(1) Dyeing cellulose fibers with direct dyes often has insufficient depth of dyeing. If there is dye in the dye bath, 1.5-5.0g/L electrolyte (NaCl, Na2SO4) can be added to promote dyeing. This pair of salt-effect direct dyes, such as direct light fast yellow 3RLL, orange (L, red BNL, red 4BL, red jade RNLL, purple BL, blue BL, B2RL, sky blue G, turquoise blue GL, green 5GLL, green GL, gray 4GL, gray GB, etc. are very effective. For direct dyes with temperature effects, a certain temperature must be maintained.

(2) Dyeing protein fibers with acid dyes, or dyeing acrylic fibers with basic dyes or cationic dyes. When the dyed sample is too dark or colored, add 3-6g/L Na2SO4 to fade or level dye. To

2. Add acetic acid

(1) Use acid dyes to dye silk, wool and other protein fibers. If the dyeing is too light and there is residual color in the dyeing solution, 0.5-2mL/L of 98% acetic acid can be added to promote dyeing. The steam valve must be closed before adding. After diluting with 10 times cold water, add slowly when the dye is running to avoid causing new colors. To

(2) Dye cellulose fibers with K-type and KN-type reactive dyes. If the large sample is darker, add 2-3 mL/L of 98% acetic acid and treat it at 90-95°C for 30 minutes to promote partial bond breakage of the dye and fade color. , Generally can be reduced by about 20%. To

(3) When dyeing silk with basic dyes or dyeing acrylic with cationic dyes, if the large sample is darker, use 2～3mI/L of acetic acid and treat it in a warm water bath at 4JD-60℃ for 20～30min to dissolve the dye. Shallow 20% to 30%. To

3. Add levelling agent

(1) Dyeing polyester and its blended fabrics with disperse dyes. When the large sample is darker than the small sample, a high-temperature leveling agent or repair agent can generally be added. If the large sample is light in color, the corresponding dye should be added, but it should be noted that the steam valve should be closed when adding to avoid color blur, and an appropriate amount of leveling agent should be added first. In addition, when additional dyeing of disperse dyes is carried out, the temperature should be raised to a certain dyeing temperature, and the temperature should be kept for 15-20 minutes, then the temperature and pressure should be lowered and the sample should be checked. To

(2) When dyeing cellulosic fiber, silk, wool and nylon fabrics with direct, acidic, neutral dyes, in principle, adding O can be used to remove the migrating dyes to achieve level dyeing. The dosage of O on the wool fabric should generally not exceed 0.3g/L. In order to prevent wool felting, you can also add wool protective agent Selebao WOK 2% to 3% (Dys-tar). When dyeing nylon with neutral dyes, if the color of the large sample is too dark or there are rungs that need to be covered, using Selego N-ER 3% to 5% (D'ystar) is very effective. To

(3) When dyeing acrylic fiber, alkali-modified polyester and silk with alkaline and cationic dyes, if the color of the large sample is slightly darker, it can be washed with hot water; if the color of the large sample is about 20%, it can be used in the dyeing residue. When it is washed out, add 2 to 4L of surfactant 1227 to achieve fading through competition dyeing. To

4. Additional brightener

When dyeing with bright colors such as red jade, rose red, purple blue, snow blue, sky blue, and brilliant purple, if the big sample is not bright enough, you can generally add 0.0015% to 0.0025% (owf) fluorescent brightener, the lighter the color, the more dosage less. For cotton textiles, the effect of fluorescent brightener 4BK is better. It has weak fluorescence, strong brilliance, low dosage, good adjustability, and has a wide range of colors and is not easy to "jump lights". The "light jumping" caused by the fluorescent whitening agent can be removed with a fluorescent stain remover that does not affect the vividness of the color. To

5. Additional dye vector

For polyester/cotton (viscose) and nylon/cotton (viscose), because polyester and nylon are hydrophobic fibers, their color is darker than that of hydrophilic fibers such as cotton and viscose. You can add 2-4mL in a 60℃ clean water bath. /L dye carrier, and then gradually increase the temperature to 80～90℃, so that the dye on the hydrophobic fiber is slowly desorbed, and the two-phase color light is consistent. Practice has proved that the dye carrier can not only dissolve disperse dyes on hydrophobic fibers, but also dissolve other dyes. When the temperature rises to 80°C, the operator must continue to take samples and keep them warm until the size matches the sample size. To

Dyeing (paint) additional method

1. When adding disperse dyes to correct the color of polyester, it is best to lower the temperature of the dyeing bath to below 80℃, and then fully dilute the pre-dissolved dyes, and add them within 5-8min, and then continue to increase the temperature to the original dyeing The temperature, heat preservation and dyeing are above 15rnin, to ensure uniform dyeing before and after, so as to reduce the influence on heat setting. To

2. If the color difference of the size sample is found after the dyed product is out of the tank, you can add dye to the larger sample or adjust the shade. When adjusting, in addition to calculating the type and quantity of dyes required on the large sample, 15%-20% of the original prescription dye should be added in the blank bath. To

3. For colors mixed with 3 to 4 kinds of dyes, such as rice gray, tile gray, incense gray, silver gray and ivory white, etc., dyes (pigments) cannot be used to repair the color difference between large and small samples.

Summary

During the production process, when the workshop master finds that there is a big gap between the workshop production and the laboratory sample, he must first understand whether there are abnormalities in the actual production process, first eliminate the abnormal problems in the production, and then communicate with the laboratory in time. Do, remember not to blindly add color more than 3 times, waste energy consumption, affect the operator's mood. Third, the master must timely and accurately adjust the recipe and sum up experience during the production process.