How to Solve the Effect of the Color of the Cotton with Reactive Stains

Reactive dyes are the most commonly used dyes for cotton dyeing, and the batch dyeing method is still the most widely used method for JnT cotton knitwear. Among the reactive dyes, based on green, bright blue, and black, the green-green color is still a single reactive vinyl sulfone type reactive dye, and the double reactive dye is a commonly used type.

In order to develop a dyeing prescription that is constant in color, ie, reproducible and streamlined, each dye manufacturer recommends different color prescriptions for light, medium, and dark colors. Dye workers can use the same manufacturer's two or three different dye prescriptions to stain different shades. These dyes are not necessarily a single dye, but may be a special mixed dye to obtain a dyeing product with high exhaustion rate and good reproducibility.

It is well known that post-dyeing treatment is an important part of reactive dyeing to obtain the required fastness properties. According to relevant statistics, the processing time of dyeing cotton knitwear accounted for 30% to 35% of the entire dyeing process, including rinsing one and washing with soap, boiling and rinsing, and fixing and processing. In order to meet the end user's fastness performance requirements, dyed products should be completely free of unfixed hydrolyzed dyes, but this may require additional soaping/rinsing/washing processes, which not only increase process time but also increase Water consumption.

Nowadays, due to the increasing scarcity of water resources, it is actually not feasible to increase the washing process, and this process still has the disadvantage of increasing the amount of sewage. In order to obtain the required wet fastness and to optimize the use of water resources, dye fixing agents are usually used to “fix” unhydrolyzed hydrolyzed dyes after one or two high-temperature soap cooks, so as not to affect the wet fastness. . In addition, the post-treatment with a cationic dye fixing agent can prevent contamination of the dyed product caused by the hydrolyzed dye under an unsuitable storage environment.

Cationic dye-fixing agents for reactive dyes are now considered to be eco-friendly products. They are not based on formal products and have different chemical properties than formal products. However, due to changes in the formulation of each dye fixing agent, its performance varies. The main problem with the dye fixing agent is that after the dye is treated, it causes changes in color and shade. Although dye fixer suppliers have promised that the product has little effect on color, it is still difficult to predict the color of dyed products after fixing.

Researchers from India's Sarex company conducted a study to investigate the correlation between the chemical properties of dye fixing agents and shade changes. In this preliminary study, the researchers performed deep and medium color staining in two groups of depths. There are dark blue, purple sauce, and dark green in dark colors, and gray, olive, and brown in medium colors. The effect of dyeing products on color shade after treatment with dye fixing agents of four different chemical types is studied.

1 test method
1.1 Fabrics After the scouring and bleaching of 100% cotton single-knitted fabrics, the fabric sampled from the production was washed in the laboratory and neutralized to a pH of 6.5.
1.2 Sumifix HF, Remazol RR, Remazol RGB are used for dyeing dark dyes; Sumifix E-XF, Cibacron FN, LevailxCA are used for dyeing medium color dyes. All dye samples were provided by the dye manufacturer for laboratory study tests. Although the colors dyed with different series of dyes do not completely match in the shade, the visual depth of the dyes in the test is kept as similar as possible to study the effect of the dye fixing agent on the shade.
1.3 Dyeing Dyeing was performed on a laboratory stained cup dyeing machine at a bath ratio of 1:10 and dyed according to the dye manufacturer's recommended standard procedure.
1.4 Soap cooking process After fixing with alkali, rinse with flowing water for 5 minutes, with a padding in the middle. Neutralize with acetic acid to a pH of 6, and rinse at this pH value and temperature of 95 for 10 min. Rinse with water again for 5 min and cook with 2% KaliumNNS and 2% SarakolPS soap at a temperature of 98 for 10 min. When the dyeing is dark, add one soap and rinse with flowing water at a temperature of 95 for 10 minutes to neutralize to a pH of 6. Rinse and Soap Water Use soft water with a pH of 6.5, bath ratio of 1:10. The soaping efficiency has been demonstrated by previous tests to ensure that the hydrolyzed dye is completely removed before the dye fixing agent is processed.
1.5 dye fixing agent treatment Select four dye fixing agents, the amount of 1% (owf), the bath ratio of 1:10, pH 6,40 treatment dyed 15min. Rolling mills maintain a uniform moisture content, 100 dry and check the moisture content.
1.6 Color Evaluation DA and DB values ​​were evaluated using a colorimetric computer and the CIELAB equation and compared with unfixed dyes.
1.7 Dye fixing agent Fixing agent 1#: SuperfixAMGNConc. Dicyandiamide Formaldehyde Fixing Agent 2#: Sarafix NF504 Epichlorohydrin polyamine polycondensate; Fixing agent 3: Sarafix. AP polyethylene polyamine polycondensate; Fixing agent 4#: Sarafix. WP tailor-made formula, ultra-low formaldehyde, stable at temperature 70 washing fastness test (AATCC61.3A).

2 Results and Discussion
The test results are shown in Tables 1 to 6.
2.1 Fixing agent on the color shade of dark green dye

When using Remazol RR to fight color dark green, the color change after the treatment with Fixing Agent #1 is the largest, and the Fixing Agent #4 has the smallest change. The four fixing agents make the color of the treated product reddish and bluish, but the degree of change is different. When remixing with RemazolRGB, the color difference is much smaller than RemazolRR, but the color is greenish. When coloring with Sumifix HF, Fix 1# has the greatest change in shade compared to the other three fixatives. Compared with Remazol RR and Remazol RGB, this dye has a yellowish hue, ie, it lacks blue light.

2.2 Fixing agent shade effect of purple sauce dyeing

When Remazol RR is used to match color purple sauce, the shade is seriously blue, among which fixing agent 1# is the most serious, fixing agent 2#, 3# is the second, fixing agent 4# is the smallest; when RemazolRGB is used for color matching, the color difference changes. It is much smaller than Remazol RR, but the shade is greenish. Among them, Fixing Agent 1# and Fixing Agent 2# have a great influence on the color shade, while Fixing Agent 4# has the lowest influence on shade; When SumifixHF is used for color matching, Fixing Agent 4# has the greatest influence on shade, and ReinazolRR and RemazolRGB. Compared with dyes, the color is reddish yellow, and the other three fixing agents have similar results.

2.3 Fixing agent on the shade of Tibetan blue dye

When using Remazol I/I/blocking navy blue, fixing agent #1 has the greatest influence on the color shade, and the color becomes bluer and greener. The other three fixing agents have similar results, but the degree of color tone change is different. Fixing agents 3 # and 4 # make the color light greener, and Fixing agent 2 # makes the color light more blue with Remazol RGB. Fixing agent 1 # makes the color light greener, so the color of the dyed product looks somewhat panning Yellow; Fixing agent #2 affects the shading of the dye and the RR dye is completely depleted, reddish and yellowish! Fixing agents #3 and #4 have more or less similar effects on the color shade. .
When Sumifix HF is used for color matching, the fixing agent 1# makes the color light become bluer and greener, and the fixing agent 3# makes the color light greener, but the degree of bluness is lighter. Fixing agent 4# makes the colored light more green. The very difference is that fixing agent 2# makes the color reddish! The effect of the color light is very different from that of the other three fixing agents.

2.4 Fixing agent effects on shades of brown dyes

When Sumifix EXF dye is used, Fixing Agent 2# makes the color shade reddish yellow, and the color shade changes the most. Fixing agents 3# and 4# make the colored light yellow, but the DA value does not change much, and the fixing agent 1# makes the colored light slightly blue and turns green, and affects the color light with the other three fixing agents. different.
When using Cibacron FN dye, fixing agent 2# reddishes the shade, while the other three fixes shade green. All the dye fixing agents make the color light blue, the highest DB value is the fixing agent #1, and the lowest fixing agent #4.
When using the LevafixCA dye, the four dye fixing agents make the color red. Fixing agent 4# has the lightest effect on the color light, and it is the only fixing agent that makes the dye shade slightly yellow.

2.5 Fixing agent on the color shade of olive dye

When using the SumitqxEXF dye, the fixing agent 2# makes the colored light reddish, and the other three fixing agents make the colored light greenish. Except fixing agent #1, the other three fixing agents had little effect on the DB value. Compared with the other three fixatives, after the fixative #1 is treated, the shade of blue is larger.
For Cibacron FN dyes, Fix 2# turns reddish shade, while the other 3 fixes shade slightly green. Fixing agents 1#, 3#, and 4# give the color yellow, while Fix 2# makes the color blue.
When using LevafixCA dye to match colors, in addition to the fixing agent 4#, the other three fixing agents make the colored light reddish, and only the fixing agent 4# makes the colored light greenish. Except for fixing agent #3, the DB values ​​of the other three fixing agents did not change substantially.

2.6 Fixing agent effects on shades of grey dyes

When using Sumifix EXF dye, in addition to Fixing Agent 2#, the colored light is infrared, and the other three fixing agents make the colored light greener. In addition, the fixing agents 2# and 3# make the colored light yellow, and the fixing agents 1#~13 make the colored light bluish. The DB value of Fixing Agent #4 did not change substantially.
With the Cibacron FN dye, similar to the SumitlxEXF dye, fixing agent #2 also reddishes the colored light, while the other three fixing agents make the colored light greener. The four fixing agents here make the color bluish. Fixing agent 3# has the smallest change in DB value. For the Levafix CA series of grey colorblocking dyes, except for the fixing agent 4# which has no effect on the color shade, the other three fixing agents make the color shade green.

3 Conclusion
For medium colors, Fixing Agent #4 has the lowest DF value. This means that Fixing Agent 4# has the lightest effect on shade, which is very important for olive, gray and brown colors. However, for dark colors, this conclusion does not exist.
For color matching of various dyes in the color, fixing agent 2# makes the color light reddish. Through experiments, it can be concluded that for medium and dark colors, formaldehyde-free dye fixing agents are superior to dicyandiamide products and have little effect on shade. Based on the above studies, dyeing workers can use the appropriate dye fixing agent to adjust the final product color shade. In order to prevent the color change caused by the dye fixing agent after the dye fixing agent is processed, the dyeing worker can build one by one. A database of dye prescriptions to study the effects of various types of dye fixing agents on their color shade.

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