1. What is the coverage of the dye?
Like the dead cotton covering property of reactive dyes or vat dyes when dyeing cotton, the covering ability of disperse dyes to poor quality polyester is called covering power here. Polyester (or vinegar) filament fabrics, including knitwear, often appear colored after being dyed with disperse dyes. There are many reasons for the color file, some of them are woven defects, and some are exposed after dyeing because of the difference in fiber quality.
2. Coverage test:
Choose low-quality polyester filament fabric, under the same dyeing conditions, use different colors of different types of disperse dyes to dye, there will be different situations, some color files are serious, and some are not obvious, which reflects that disperse dyes have different color files Degree of coverage. According to the gray standard, the serious color difference is level 1, and the color difference is level 5.
The coverage of the disperse dye on the color file depends on the structure of the dye itself. Most of the dyes with high initial dyeing rate, slow diffusion, and poor migration have poor coverage on the color file. Coverage also has a certain relationship with sublimation fastness.
3. Inspection of polyester filament dyeing performance:
On the contrary, the use of disperse dyes with poor coverage can detect the quality of polyester fibers. The unstable fiber manufacturing process, including changes in drafting and setting parameters, can cause inconsistencies in fiber affinity. Dyeing quality inspection of polyester filament, usually with the typical Eastman Fast Blue GLF (CI Disperse Blue 27) dye with poor covering power, dyeing depth 1%, dyeing at 95～100℃ for 30 minutes, washed and dried according to the degree of color difference Rating rating.
4. Prevention during production:
In order to prevent the occurrence of color files in production, the first is to strengthen the management of the quality of polyester fiber raw materials. The weaving mill must use up the remaining yarn and then change the product. For original blanks of known inferior quality, disperse dyes with good covering power can be selected to avoid large-scale reduction of finished products.