i. Coverage: Polyester fibers have undergone various heat treatments during the manufacturing process, resulting in uneven physical structures such as fiber crystallinity, distribution and molecular orientation, resulting in differences in dye uptake, resulting in so-called stripes, warp Shadow. (The property of covering the dyed flowers due to uneven fiber structure is called hiding.
ii. Dyeing migration: It refers to the migration of dyes between fibers due to raising the temperature or adding auxiliaries after the dyes are dyed on the fibers. Dyes with good migration properties are easier to obtain level dyeing, so good or bad migration properties are an important factor for level dyeing. Generally, E-type disperse dyes have good dyeing properties, while S-type disperse dyes have poor dyeing properties.
iii. Dyeing rate
The dyeing process of disperse dyes on polyester fibers is divided into three stages:
a. Disperse dyes diffuse to the fiber surface in a dispersed state or a slightly melted state and a dissolved state.
b. Disperse dyes are adsorbed on the surface of polyester fibers.
c. Disperse dyes diffuse into the polyester fiber.
iv. Promotion rate
When dyeing dark colors, dyes with high lifting rate should be selected, otherwise the utilization rate of dyes will not be high.