(A) of the cationic dye structure and properties of cationic dyes order to adapt to the dyeing of acrylic fibers, improved on the basis of the basic dye, developed the new dye. checkered flags Such dyes in aqueous solution can dissociate into positively charged pigment cation, it is referred to as cationic dyes. According to the structural characteristics of the cationic dye structure carried by cationic group, the dye is divided into of Conjugated isolated two categories. The basic dye and cationic dyes are conjugated. Conjugated system in the dye dye hair color, while the cationic group reactivity of large sensitive locations in the structure of dyes, such dyes resistant to heat and light stability is poor, but its bright color,checkered flags too high color yield, levelness better. The cationic group in the structure of the other cationic dyes and the Custom Decorative Garden Flags Wholesale dye between the mother's hair color system separated from each other, so called isolated cationic dyes. The high reactivity of the cationic group does not participate in the dye conjugate of the parent dye hair color system can remain stable under the action of light, heat, such dyes is relatively heat-resistant, high light fastness, but because charge concentration of the strong binding of the fiber, it is difficult to get a leveling effect.
Cationic dyes are more sensitive to the pH of dye bath, relatively stable in acid medium, good solubility. However, if the pH of the solution is too high, especially under alkaline conditions, checkered flags the dye-prone shade change, even decomposition, sedimentation; if the pH value is too low, can also cause changes or decomposition of the dye shade. Therefore, the cationic dye, the pH value is generally controlled at 4 to 5. In addition, the cationic dye in the solution easily combined with anionic additives and dyes to generate precipitation or a coke-like material, it should be avoided in principle with the anionic compounds with bath, but can also take advantage of this nature, selection of the appropriate anion additives retarding or preparation of dispersed cationic dyes. Adding neutral electrolyte can also be retarding the cationic dye staining, dyeing results.
(B) cationic dye principle of cationic dyes dyed acrylic colored cationic dye cation fiber with negatively charged groups and salt combination, namely:
Fiber-COOH CI-dye – → fiber-COO-dye HCl checkered flags
This combination belongs to locate the adsorption process, the cationic dye staining of the eye-lun can include under the three processes.
An adsorption acrylic dissociation of acidic groups in the water leaving the fiber with a negative charge, easily absorbed the dye cation to the negatively charged fiber surface to be and with the continuous diffusion of the dye ions inside the fiber, the fiber surface charge increases, the fibers again The adsorption of dye. Wind Flags Advertising
(2) proliferation of the spread of dye to fiber is a complex process. Since the negative charge on the cationic dye and fiber groups strong Coulomb gravity, making the diffusion becomes more difficult, and often requires the use of increased temperature of the dye molecules. In acrylic dyeing with cationic dyes, checkered flags we must strictly control the temperature, in order to facilitate the stain evenly through.
3 solid dye fixation process of the salt of the anionic groups on the dye cation and the fiber, it is basically irreversible.
Visible from the above three processes, make the cationic dye smoothly
and evenly through the ground dyed acrylic, must try to control the rate of adsorption of the dye on the fiber, and then try to strengthen the diffusion rate of dye in the fiber inside and to minimize the spread of the dye in the fiber within the resistance . Therefore, we must pay attention to the following factors:
Temperature: (1) acrylic dyeing process, the temperature on the one hand can be given dye diffusion energy, on the other hand can make the fiber extruded to reduce the diffusion resistance
of the dye within the fiber. When the temperature is below the glass transition temperature of the acrylic dyes on the fiber, the adsorption rate is slower; speed up when temperature rises above