In actual production, it is impossible for there to be no difference in the size of dyeing samples, and effective methods should be adopted to correct them. Commonly used solutions are briefly described below.
1. Cold water cleaning
In cotton and its blended interwoven fabrics, after the cotton component is dyed with direct dyes or reactive dyes, floating color or luster will appear If it becomes dull, it is generally necessary to continue washing with water, or add additives to the water bath for washing. If the water hardness is high, 0.5~2g/L chelating dispersant can be added to improve it.
2. Washing with warm water
When dyeing polyester blended interwoven fabrics, There are many types of dyes and auxiliaries used, and they can be washed at 40°C to facilitate the dissolution of residues stained 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.
3. Hot water cleaning
Hot water cleaning is mostly used for Silk or synthetic fibers and their interweaves dyed with acid, direct and basic dyes. If the color is darker, 1 to 20% of the dye needs to be removed, and you can use hot water washing at 70 to 80°C. For silk fabrics, 0.3 to 0.5L of leveling agent can be added to the hot water bath; for polyester, nylon and other synthetic fiber blended fabrics, 0.5 to 1.0L of patching agent or patching agent can be added. Dye carrier.
Since the amount of additives added in the hot bath is small, the fabric only needs to be washed with running water to room temperature. If dyed fabrics are treated with cationic fixatives and softeners, it is best to add 2 to 4L of dispersant DAM to the hot bath. In principle, hot water washing (repair) should be carried out on the original dyeing equipment. For example, after jig dyeing of nylon, acetate fiber and interwoven silk, if the overflow machine (rope type) is used for hot water washing, the fabric will cause permanent wrinkles.
Auxiliary addition method
1 .Add electrolyte
(1) When using direct dyes to dye cellulose fibers, the dyeing depth is often not enough for large samples. If there is still dye in the dye bath, add 1.5-5. Og/L electrolyte (NaCl, Na2SO4) promotes staining. This is suitable for salt effect direct dyes, such as direct light fast yellow 3RLL, orange (L, bright red BNL, red 4BL, ruby RNLL, purple BL, blue BL, B2RL, sky blue G, emerald blue GL, green 5GLL, green GL, gray 4GL, gray GB, etc. are very effective. For temperature-effect direct dyes, a certain temperature needs to be maintained.
(2) Use acid dyes to dye protein fibers, or use basic dyes or When dyeing acrylic fiber with cationic dyes, if the color of the dyeing sample is too dark or has flowers, 3~6g/L Na2SO4 can be added to fade or level dye it.
2. Add acetic acid
(1) Use acid dyes to dye silk, wool and other protein fibers. When there is residual color, 0.5-2mL/L of 98% acetic acid can be added to promote dyeing. The steam valve must be closed before adding, dilute it with 1O times of cold water, and add it slowly while the dye is running to avoid causing new color flowers.
(2) Use K-type and KN-type reactive dyes to dye cellulose fibers. If the sample is too dark, add 2-3mL/L of 98% acetic acid at 90-95 ℃ treatment for 3Omin, prompting the dye to partially break the bond and eliminate the color, which can generally reduce the color by about 20%.
(3) When dyeing silk with alkaline dyes or acrylic dyes with cationic dyes , if the large sample is too dark, you can use 2~3mI/L acetic acid and treat it in a warm water bath at 4JD-60℃ for 2O~30min to dissolve the dye and reduce the color by 20%~30%.
3. Add leveling agent
(1) Use disperse dyes to dye polyester and its blended interwoven fabrics When the large sample is darker than the small sample, you can generally add a high-temperature leveling agent or repair agent. If the large sample is lighter in color, you should add the corresponding dye, but be careful to close the steam valve when adding to avoid color blooms. Add an appropriate amount first. Leveling agent. In addition, when additional dyeing is carried out with disperse dyes, the temperature must be raised to a certain dyeing temperature and kept for 15-20 minutes, and then the temperature and pressure should be lowered and the sample should be checked.
(2) When dyeing cellulose fiber, silk, wool and nylon fabrics with direct, acidic, neutral and other dyes, in principle, flat O can be used to remove the migrating dye and achieve level dyeing. The amount of flat O on wool fabrics is generally It cannot exceed 0.3g/L. In order to prevent wool from felting, you can also add wool protection agent WOK 2% to 3% (Dys-tar). When dyeing nylon with neutral dyes, if the color of the large sample is too dark or When there are rungs, etc. that need to be covered, the color Lego N-ER 3% ~ 5% (D’ystar) has excellent results.
(3) Dye with alkaline and cationic dyes When dyeing acrylic, alkali-modified polyester and silk, if the color of the dyed sample is slightly darker, hot water can be used to clean it; if the color of the sample is about 20% darker, 2 to 4L of surfactant can be added when the dyeing residue is basically washed away. Agent 1227 achieves fading through competitive dyeing.
4. Add whitening agent
Dye ruby and rose When using bright colors such as red, violet blue, snow blue, sky blue and brilliant purple, if you feel that the large sample is not bright enough, you can generally add 0.0015% to 0.0025% (owf) fluorescent whitening agent. The lighter the color, the less dosage. For cotton textiles, the fluorescent whitening agent 4BK has a better effect. It has weak fluorescence, strong brightness, low dosage, good adjustability, and is adaptable to a wide range of colors and is not easy to “jump”. “Light popping” caused by fluorescent whitening agents can be removed with a fluorescent stain remover that does not affect the brightness of the color.
5. Additional dyeing vector
For polyester-cotton (viscose) and nylon-cotton (viscose), since polyester and nylon are hydrophobic fibers, their color is better than hydrophilic fibers such as cotton and viscose. Deep, you can add 2-4mL/L dyeing carrier into the 60℃ clean water bath, and then gradually raise the temperature to 80-9O℃ to slowly desorb the dye on the hydrophobic fiber to achieve the same two-phase color. Practice has proven that the dyeing carrier can not only dissolve disperse dyes on hydrophobic fibers, but also has the ability to dissolve other dyes. When the temperature rises to 80°C, the operator must continuously take samples to check, and generally keep the temperature until the large and small samples match.
Additional dyeing (pigment) method
1. For polyester When adding disperse dyes for color correction, it is best to first lower the dye bath temperature to below 80°C, then fully dilute the previously dissolved dyes, and finish adding them within 5 to 8 minutes, and then continue to increase the temperature to the original dyeing temperature for heat preservation dyeing. 15rnin or more, ensure the front and back colors are evenly dyed to reduce the impact on heat setting.
2. If there is a color difference between the large and small samples after the dye comes out of the vat, you can add additional dye or adjust the color light on the large sample. When adjusting, in addition to calculating the type and quantity of dyes required on the large sample, 15% to 20% of the original prescription dyes should also be added to the blank bath.
3. Colors made with 3 to 4 dyes, such as rice gray, tile gray, incense gray, silver gray and ivory white, cannot be repaired with dyes. Color difference between large and small samples.
During the production process, the workshop master found that the gap between workshop production and laboratory samples was too large In large cases, we must first understand whether there are any abnormalities in the actual production process, first eliminate the abnormal problems in production, and secondly communicate with the laboratory in a timely manner. When re-doing the process, remember not to blindly add color more than 3 times, which wastes energy and affects Operator emotions. Third, during the production process, the master must make timely and accurate preparations and sum up experience. </p