Dyeing of Cotton With Cold Brand Dye

Theory

Reactive dyeing is the most important method for the coloration of cellulose fibers. Reactive dyes have a low utilization degree compared to other dyestuffs, since the functional group also bonds to water, creating hydrolysis. The reactive dye reacts with fabric in the presence of alkali and adheres as a part of the fiber. Three main mechanisms are exhaustion, fixation, and finally washing off. First, exhaustion happens in the presence of electrolytes. Then fixation happened under the influence of alkali. Finally, washed off the fabric to remove unfixed dye from the material surface. Softeners can be used to soften the surface of the fabric.

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Recipe

Chemicals / Parameters	Required Amount
Reactive red	2%
Glauber salt	60 g/L
Soda ash	18 g/L
Wetting agent	1 g/L
Leveling agent	1 g/L
Sequestering agent	1 g/L
Temp ✕ Time	60℃ ✕ 60 mins
pH	10-11
M:L	1:10
Sample weight	10 gm
Neutralization
Acetic acid	1 g/L
Temp ✕ Time	50℃ ✕ 10 mins
Soaping
Detergent	1 g/L
Temp ✕ Time	70℃ ✕ 10 mins
Softening
Softener	4 g/L
Temp ✕ Time	40℃ ✕ 10 mins

Functions of the Chemicals Required

Wetting agent: It accelerates the wettability of material in solution, thus helping to the easy penetration of chemicals into the substrate. It reduces the surface tension of water to allow it to spread drops on a surface, increasing the spreading abilities of a liquid.

Sequestering agent: A sequestering agent is a substance that suppresses as property or reaction of metal ions without the removal of that metal from the system.

Leveling agent: Levelling agent tends to slow down the dye uptake on the fibers, helping to produce a more uniform color in the textile fiber.

Common salt: Salt is used as an electrolyte. This electrolyte neutralizes the negative charge formed in the fiber surface and puts extra energy to increase dye absorption.

Acetic acid: Its function is to control pH in the process.

Soda ash: Soda ash creates proper pH in the dye bath and works as the dye-fixing agent. It helps in forming a strong covalent bond between the dye with the fabric.

Detergent: For emulsifying fats, oils, and waxes. Removes the unfixed dyes from the surface of the fabric.

Softener: Softener makes the surface of the fabric smooth and softens it.

Recipe Calculation

Here, M:L = 1:10

Sample weight: 10 gm

Total liquor : 10 ✕ 10 = 100 ml

For Reactive red;

100 gm fabric needed 2 gm of dye

So, 10 gm fabric needed = (2 ✕ 10) / 100 = 0.2 gm of dye

Chemicals = (g/L ✕ Total liquor) / 1000

Glauber salt = (60 ✕ 100) / 1000 = 6 gm

Soda ash = (18 ✕ 100) / 1000 = 1.8 gm

Wetting agent = (1 ✕ 100) / 1000) = 0.1 ml

Levelling agent = 0.1 ml

Sequestering agent = 0.1 gm

Total = (0.1 + 0.1) = 0.2 ml

Freshwater = (100-0.2) = 99.8 ml

Shade Attachment

Dyeing Curve

Conclusion

Reactive dyeing is becoming very popular for fabric coloration because of some specific properties like a wide range of shades, reproducibility, good fastness, and simple application procedure.