Auxiliaries for Yarn Dyeing | Different Chemicals Used in Yarn Wet Processing

Various Pretreatment Chemicals:
Bleaching Detergents ( Decols SN, Keiralon 0L,Redol 10s ) : Mostly these are high alkaline detergents. We have to use these for removal of dirt / dust & strains. 
Yarn dyeing
Alkalis (Soda Ash / Caustic Soda or Soda bi carbonate or buffer alkali): We are using alkalis for saponifying oil / waxes & greases present in cotton & other materials.

Oxidizing Agent H2O2 (Hydrogen per oxide): For removing micro ingredients like minerals, fertilizer, insecticides & pesticides we have to use oxidation principle.

Stabilizer (Stabilol P): H2O2 is unstable at high temperature, to keep it stable & to keep oxidation process alive we have to use this in bleaching bath.

Sequestering Agent (Secron, Triton TB, Cibacell DBC): Water contains certain percentage of calcium, magnesium and other minerals which determine the hardness of water, this hardness can affect dyeing procedure. This can be reduced by using sequestering agent.

Anti Oxidants: Any percentage of H2O2 or any other left over from bleaching process can affect dyes & dyeing process, So it is advised to use anti oxidants before dyeing process.

Acid for Neutralization (Acetic acid, formic acid): Scouring, Half Bleach, Semi Bleach all are done in alkaline bath and before going to next bath we need to neutralize it by some organic acid.

Various Dyeing Chemicals:
Leveling agent & Dispersing Agent (Leveler 5L, Redol 200L, Setamol ): We have to use all these auxiliaries /chemicals for dispersing dyes equally in dyeing bath, it will help dyes molecule to penetrate in cone & sit on the surface of material evenly & equally.

Reactive Dyes Chemicals:
Alkalis i.e. Caustic soda, Soda Ash, Sodium bi carbonate, Sodium phosphate: All these alkalis can be used in reactive dyeing process. The selection & requirement percentage depends on class of dyes, dyeing method & pH Requirement of the process & dyeing machine.

Salts or Carrier: Common salt & Gulber salt are the common commercial electrolytic that we can use in dyeing.

Neutral Soap: In soaping we require neutral soap & good sequestering agent to remove superficial dyes & salt.

Fixers (Tinofix, Rewin TN): For Surface coating, fixation of loosely bonded dyes molecules, and for catalyzing unreacted reactive dyes molecule some fixers can also be used up to certain percentage only.

Disperse Dyes Chemicals:
Acid (Formic acid, Acetic acid, Buffer acid): All these acids can be used for acidic pH of dyeing bath whose percentage depends on selected dyes range, dyeing method or dyeing machine.

Reduction Clean Chemicals: Sodium hydrosulphite (hydrous) & caustic soda is a good reduction clean combination.

After Treatment Chemicals:
Softener: There are three types of softeners.
1) Cationic or slightly cationic, these types of softeners are used for dyed material.
2) Non ionic, this special class is used for white and sensitive light shade because it has no yellowing effect
3) Anionic softeners, these type of softeners are required for particular types of finishing

Wax: Good wax is also useful for good quality hard winding & its farther consequent processes.

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Mazharul Islam Kiron is a textile consultant and researcher on online business promotion. He is working with one European textile machinery company as a country agent. He is also a contributor of Wikipedia.

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