Migrating after dyeing means that after polyester is dyed with disperse dyes, when treated at high temperature (such as heat setting), disperse dyes can produce a kind of thermal migration due to the influence of additives. Thermal migration is a redistribution phenomenon of disperse dyes in two-phase solvents (polyester fibers and additives). Therefore, all additives that can dissolve disperse dyes can produce thermal migration. If there is no second phase solvent, it is impossible to generate thermal migration; if the second phase solvent is weakly soluble in dyes, or the amount of the second phase solvent is small, the thermal migration phenomenon will also be weakened accordingly. The reason for the thermal migration phenomenon is that the auxiliaries in the outer layer of the fiber dissolve the dye at high temperature, and the dye spreads from the inside of the fiber through the high temperature of the fiber capillary and migrates to the surface of the fiber, so that the dye accumulates on the surface of the fiber, resulting in a series of effects. , such as color change, decrease in color fastness, etc. This decrease in fastness is collectively referred to as heat migration fastness.
Factors Affecting Thermal Migration Fastness of Disperse Dyes
1. The thermal migration of disperse dyes is related to the molecular structure of the dye itself, but has no absolute relationship with the sublimation fastness of the dye, that is to say, the thermal migration fastness of disperse dyes with good sublimation fastness is not necessarily good;
2. The wide application of non-ionic surfactants is the main reason for the thermal migration of disperse dyes. Due to the different solubility of disperse dyes with different structures in non-ionic surfactants, the degree of thermal migration fastness decline of different dyes is different. ;
3. The application of amino silicone microemulsion softener is also the reason for the decrease of thermal migration fastness of disperse dyes; since the emulsifier in the softener becomes the second solvent of disperse dyes, it aggravates the thermal migration of disperse dyes after dyeing , affecting the heat migration fastness.
Solve the heat migration fastness of disperse dyes
1. Use dyes with good thermal migration fastness;
2. Reduce the use of silicone oil containing a large amount of emulsifier in the setting;
3. Low temperature over-setting (most factories do this);
4. Add auxiliaries such as anti-heat migration agent, but it will affect the hand feel and hydrophilicity to a certain extent. It will not improve the heat migration fastness. The color fastness to washing after high temperature setting may decrease by about half a grade promote.