Dyeing of Polyester Fabric with Disperse Dye:
Polyester is the synthetic fiber derived from coal, air, water, and petroleum. Polyester has been one of the most popular fibers, second to cotton as measured by production tonnage in recent years. Polyester can be very difficult to dye properly. The dyeing of hydrophobic fibers like polyester fibers with disperse dyes may be considered as a process of dye transfer from liquid solvent (water) to a solid organic solvent (fiber). In this article I will discuss different problems and their solutions of polyester dyeing with disperse dyes.
Polyesters are essentially undyeable below 70–80°C, leaving only a 20–30°C range for increasing the dyeing rate before reaching the boiling temperature. At any temperature, the rate of dyeing of polyester with a given disperse dye is very much lower than for cellulose acetate or nylon fibers. The rate of diffusion of disperse dyes into the polyester below 100°C is so low that dyeing at the boil does not give reasonable exhaustion. The rate of dyeing is higher for dyes of small molecular size that have higher diffusion coefficients. Dyeing is faster when using fiber swelling agents called carriers to improve the fiber accessibility, or when dyeing at higher temperatures above 100°C to increase the dye diffusion rate. Dyeing of polyester with disperse dyes have good light fastness. This does not always correlate with the light fastness on other fibers such as cellulose diacetate.
Dyeing flow chart of 100% polyester with disperse dye is shown in below:
Fabric load
↓
Water level – as required
↓
Raise temperature to 60°C
↓
Add Feloson NOF
↓
Raise temperature to 90°C and run time 10 min
↓
Drain
↓
Water level – as required
↓
Raise temperature to 45°C
↓
Add Neutracid RBT (non-volatile acid) and run time 10 min
↓
Drain
↓
Water level – as required
↓
Raise temperature to 45°C
↓
Dye dosing for 10 min
↓
Raise temperature to 130°C and run for 45 min
↓
Drain
↓
Water
↓
Cooling at 700°C and sample cheek if shade ok then bath drop
↓
Hydrose + Caustic at 800°C for 20 min
↓
Hot wash
↓
Acetic wash at cold temperature for 10 min
↓
Acetic acid + Softener is added at 450°C and run for 10 min
↓
Cold wash
↓
Fabric unload
Dyeing Problems and Their Solution of Polyester with Disperse Dye:
Though dyeing of Polyester with Disperse Dye is very compatible, they have some problems occur during dyeing. Problems and solution are given in table:
| Problems | Solution |
| Dyeing levelness |
|
| Color-repetition |
|
| Colorresilience (Thermomigration) |
|
Other problems of dyeing polyester with disperse dyes:
- Variations in the dyeing behavior of the fibers due to variations in their production or thermal pretreatments
- Hard water can have significant effect on the color value of disperse dyes
- Moir effect due to heat setting problems and uneven relaxation of fabric tensions
- Off shades is the biggest problem and it occurs due to combination of various factors
Following are also occurred during polyester dyeing with disperse dyes:
- Oligomers
- Pilling
- Migration
Oligomers: Oligomers are still the biggest problem in wet processing of polyester fabric leading to variety of problems.
Pilling: Pilling is the formation of fiber balls on the fabric surfaces, when a group of loose, or short and broken fibers get entangled or accumulated on the fabric after abrasion. The tiny balls are pill. It cannot be eliminated totally, but it can be minimized by proper handling during fabric washing.
Migration: Migration is the shifting of the color to the surrounding areas. It is the unwanted reaction between the dye and the fiber. Migration is a serious problem encountered both in dyeing and printing. Dye migration is generally more on 100% polyester fabrics. It results in the coloring of unintended areas. Hence, any fabric containing the polyester is vulnerable to dye migration and bleeding.
You may also like:
- Dyeing of Polyester Fabric with Disperse Dyes
- An Overview of Polyester and Polyester Dyeing
- Printing of Polyester Fabric with Disperse Dyes
- Dyeing of Cotton / Polyester Blended Knit Fabric with Reactive / Disperse Dyes Using Jet Dyeing
- Polyester/Cotton (P/C) Blends Fabric Dyeing: Recipe, Parameters, Flowchart and Dyeing Curve
- Dyeing of Polyester Cotton Blended Fabric in Single Bath
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.
