Flow Chart of Yarn Dyeing Process

Yarn Dyeing: 

Yarn dyeing is a special type of dyeing process. This dyeing process is slightly different from woven or knit dyeing. Dyed yarns are used for making stripe knit or woven fabrics or solid dyed yarn fabric or in sweater manufacturing. Yarn can dye in two forms, package or hank form. The flowchart of yarn dyeing can be divided into three stages. Preparatory process, dyeing, and after-treatment process. Process flow chart of yarn dyeing is as follows:

Flow Chart of Yarn Dyeing Process

Preparatory process

Soft winding
↓
Batching
↓
Batch loaded
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Demineralization (50˚C, 20 min; PH=4.5)
↓
Scouring & bleaching (100˚C×40 min.)
↓
Drain
↓
Rinse
↓
Drain
↓
Neutralization with acid (50°C ×20 min)
↓
Hot Wash with peroxide killer (60˚C,20 min.)
↓
Drain
↓
Dyeing
↓
Leveling agent & Salt (60° × 20 min; PH=6)
↓
Color dosing (60°C×20 min.)
↓
Run time = 10 min. (60°C)
↓
Color migration (80°C × 20 min.)
↓
Cooling (60°C)
↓
Level Check
↓
Soda dosing (60°C×30 min.)
↓
Dyeing run (Dark-60°C×60 min;Medium-60°C×40 min;Light-60°C×
30 min)
↓
Dyeing sample check
↓
(If Ok)
↓
Drain
↓
After-treatment
↓
Rinse (with cold Water)
↓
Neutralization after dyeing (50°C×20 min.)
↓
Drain
↓
Soaping (Hot wash)
↓
Drain
↓
Rinse
↓
Add finishing chemical(60°C×20 min)
↓
Drain
↓
Unload

Dyes could be used on vegetable, animal, or man-made fibers. Textile dyes include acid dyes, used mainly for dyeing cotton. That has a strong affinity for cellulose fibers. Mordant dyes require the addition of chemical substances, such as salts to give them an affinity for the material being dyed. They are applied to cellulose fibers, wool, or silk after such materials have been treated with metal salts. Sulfur dyes, used to dye cellulose, are inexpensive but produce colors lacking brilliance. Azoic dyes are insoluble pigments formed within the fiber by padding, first with a soluble coupling compound and then with a diazotized base. Vat dyes, insoluble in water, are converted into soluble colorless compounds by means of alkaline sodium hydrosulfite.