What are the performance indicators of reactive dyes

Dissolved

High -quality active dye products should have good water solution. The concentration of the solubility and the preparation of the dyeing solution is related to the size of the selected bath ratio, how much the electrolyte is added, the dyeing temperature, and the amount of urea. Active dyes used in printed or rolled dyes should be selected with a variety with a solubility of about 100 grams / liter. It is required that the dye is completely dissolved, no turbidity, no color points. Thermal water can accelerate dissolution, and urea has a soluble effect, and electrolytes such as salt and Yuanming powder will reduce the solubility of dyes. When the active dye is dissolved, the alkali agent should not be added at the same time to prevent hydrolysis of the dye.

Direct nature

Directability refers to the ability of active dyes to be absorbed by fiber in the dye solution. Active dyes with high solubility are often low. Continuous dyeing and printed varieties should be used. The dyeing equipment of the bath, such as rope -like dyeing and twisted gauze staining, should be preferred to use high direct dyes. The dyeing method of rolling rolling (cold rolling pile), the dyeing fluid is transferred to the fiber by dipping, and it is easy to get evenly dye with dyes with a slightly lower directability.

The direct size of the active dye is represented by a balanced dyeing percentage (ie, color) or color layer analysis.

Proliferation

Diffusion is the ability to move inside the fiber to the fiber, which is conducive to the diffusion of dyes molecules. Dyes with large diffusion coefficients, high response rates and color fixing efficiency, as well as the degree of dyeing and dyeing. The quality of the diffusion performance depends on the structure and size of the dye, the larger the molecule, the more difficult to spread. Dyes with fibrous affinity are strongly adsorbed by the fiber, and it is difficult to spread. Usually, it increases the temperature to accelerate the spread of dyes. Add electrolyte to the dye solution, and the diffusion coefficient of the dye decreases.

The diffusion performance of the dye is usually a thin film method. Take the sticky film (glass paper) and immerse them in distilled water. The thickness before immersion is 2.4 wires, and the thickness of 4.5 after immersion for 24 hours. During the measurement, this film is stacked into a certain thickness as needed, and pressed on the glass plate to remove the bubbles. Then sandwiched in the middle of the two splints with a rubber cushion, one of which there is a round hole in the middle of the splint. The dyeing solution can only spread to the film layer through this hole, and immerse the splint film in the dyeing solution at 20 ° C for 1 hour. , Then rinse with water to observe the number of layers of the dye -dyed film and the color of each layer of dye. The number of diffusion layers has a certain correlation with the semi -dyeing time. The semi -dye time is short and the number of diffusion layers is large.

Lively

The reactivity of active dyes usually refers to the strength of the dye and cellulose hydroxyl group. The dyes with strong reactivity can be completed at room temperature and weak alkali. Lost the ability to be stained by hydrolysis. The weakly reactive dye needs to be combined with the fiber key under higher temperature conditions, or the hydroxyl group of the fiber gauze is activated with a strong alkaline, which prompts the dye reaction to be fixed on the fiber.

The reactivity of the active dye in the same model is roughly the same. The strength of the reactivity depends on the chemical structure of the dye activated base. The second is the connection group between the dye body and the active group, which has a certain impact on the reactivity of the dye. In addition, due to the influence of the pH value, the general pH value increases, and the response speed will increase. As for temperature, it is also a factor affecting the reaction speed. The temperature increases and the response speed is fast. Each temperature increases by 10 ° C, the reaction speed can be increased by 2-3 times. Therefore, after printing, after drying or steaming, the dye and fiber can react.