The so-called dyeing refers to the process of dye transfer (or other media) to fiber transfer and fiber dyeing. Dyeing balance Balanced dye uptake percentage : When the dyeing reaches equilibrium, the amount of dye adsorbed on the fiber accounts for the percentage of the total dye input. Plain Dyed Roma Fabric,Ponte Roma Fabric,Knitted Ponte Roma Fabric,Nr Ponte Roma Fabric SHAOXING XIANCHENG TRADING CO.,LTD , https://www.xcxssfabric.com
Dye dyeing process:
The dyeing process and the dyeing process usually referred to are not the same .
Several stages of the dyeing process:
1. Dye transfer from dye liquor to fiber interface
Diffusion boundary layer : The layer of liquid that is mainly due to the diffusion of the dye itself to the surface of the fiber, called the diffusion boundary layer.
It is one of the important ways to speed up the dyeing by strengthening the circulation of the dye liquor and increasing the flow rate of the dye liquor. This will not only speed up the dye to reach the fiber surface, but also improve the leveling effect.
2. The dye molecules are quickly absorbed by the fiber surface after the dye is close to the fiber in the diffusion boundary layer, and the hydrogen bonds, Van der Waals, or Coulomb's gravity bonds occur between the dye molecules and the fiber surface molecules.
3. After the dye is adsorbed on the surface of the fiber, a concentration difference of the dye is formed inside and outside the fiber, so that the dye is diffused inside the fiber and fixed inside the fiber.
Factors affecting the dyeing process
Dyes Movement State: Dyeing Fluid Flow Diffusion Adsorption Diffusion
Important influencing factors:
1. The dye molecular structure 1~6 is the same as the left 1~4
2. Dissolved state of the dye 7. Fiber surface characteristics 5. Fiber microstructure
3. Other composition and charge in the dye liquor 6. Fiber chemical structure
4. temperature
5. Bath ratio, dye flow
6. p H
Dyeing balance: When the dyeing reaches a certain level, the dye adsorption and desorption rates are equal, and the concentration of the dye solution on the dye liquor and fiber does not change, ie, the dyeing equilibrium state is reached.
The dyeing process is the result of the movement of a large number of dye molecules and is a macroscopic result. It is often measured by the concentration change of dyes in dye liquors and fibers, rather than the behavior of individual dye molecules.
Percentage of dye uptake : The percentage of dyes adsorbed on the fibers as a percentage of the total dye input.
Dyeing rate : The rate of change of the dye concentration on the fiber to the time of dyeing.
Dyeing rate curve: The curve of the dye uptake versus time (or the dye concentration versus time curve on the fiber) is called the uptake rate curve.
Adsorption isotherm: The relationship between the concentration of dye on the fiber and the concentration of the dye in the dye solution at a constant temperature when the dyeing reaches equilibrium.
Balanced Adsorption: The concentration of dye on the fiber when dyeing reaches equilibrium.
Staining saturation: The concentration of dye on the fiber no longer increases with increasing dye concentration in the dye. At this time, the dye concentration on the fiber becomes the saturation value of the dye.
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