What is Yarn Dyeing?
Dyeing can be done during any stage, from the raw fiber right through to the finished garment. Yarn dyeing is a less expensive process used in textile mills to color yarns. Yarn dyeing is carried out after fiber has been spun into yarn. In this method, the dyestuff penetrates the fibers to the core of the yarn. The process is mainly used to produce various effects of stripes, checks, plaids or other multicolor designs with different colored yarns in the weaving and knitting process. Moreover, threads for sewing and embroidery purposes are all dyed at the yarn stage.
Yarns may be dyed in different forms:
- Hank dyeing
- Package dyeing (cone dyeing)
- Slasher dyeing
- Rope dyeing
Different types of chemicals and auxiliaries are used during yarn dyeing process. In previous article I have discussed list of chemicals and auxiliaries for fabric dyeing. In this article I will discuss different chemicals and auxiliaries are used in yarn dyeing operation.
Various Pretreatment Chemicals of Yarn Dyeing:
1. Bleaching Detergents (Decols SN, Keiralon 0L,Redol 10s ): Mostly these are high alkaline detergents. We have to use these for removal of dirt / dust and strains.
2. Alkalis (Soda Ash / Caustic Soda or Soda bi carbonate or buffer alkali): We are using alkalis for saponifying oil / waxes and greases present in cotton and other materials.
3. Oxidizing Agent H2O2 (Hydrogen per oxide): For removing micro ingredients like minerals, fertilizer, insecticides and pesticides we have to use oxidation principle.
4. Stabilizer (Stabilol P): H2O2 is unstable at high temperature, to keep it stable and to keep oxidation process alive we have to use this in bleaching bath.
5. 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.
6. Anti Oxidants: Any percentage of H2O2 or any other left over from bleaching process can affect dyes and dyeing process. So it is advised to use anti oxidants before dyeing process.
7. 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 Yarn Dyeing Chemicals:
Leveling agent and 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 and sit on the surface of material evenly and 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 and requirement percentage depends on class of dyes, dyeing method and pH Requirement of the process and dyeing machine.
1. Salts or Carrier: Common salt and Gulber salt are the common commercial electrolytic that we can use in dyeing.
2. Neutral Soap: In soaping we require neutral soap and good sequestering agent to remove superficial dyes and salt.
3. 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:
2. Reduction Cleaning Chemicals: Sodium hydrosulphite (hydrous) and caustic soda is a good reduction clean combination.
After Treatment Chemicals of Yarn Dyeing:
1. Softener: There are three types of softeners.
- Cationic or slightly cationic, these types of softeners are used for dyed material.
- Non ionic, this special class is used for white and sensitive light shade because it has no yellowing effect
- Anionic softeners, these type of softeners are required for particular types of finishing
2. Wax: Good wax is also useful for good quality hard winding and its farther consequent processes.
You might also like:
- List of Chemicals and Auxiliaries Used for Fabric Dyeing
- List of Chemicals and Auxiliaries Used in Textile Wet Processing
- Typical List of Chemicals Used in Dyeing Mill
- List of Garment Washing Chemicals and Their Functions
- Different Types of Denim Washing Chemicals and Their Functions
Founder & Editor of Textile Learner. He is a Textile Consultant, Blogger & Entrepreneur. He is working as a textile consultant in several local and international companies. He is also a contributor of Wikipedia.