What are main factors affecting the thermal migration of disperse dyes?（1）

(1) The relationship between fiber dyeing depth and thermal migration

There is a certain contrast between the dyeing depth of polyester fiber and the thermal migration of disperse dyes, that is, the deeper the color, the greater the thermal migration of the dye during high-temperature dry heat treatment, and the more serious the impact on the dye quality.

(2) The relationship between heat treatment temperature and thermal migration

Under normal conditions, the higher the temperature of dry heat treatment after polyester dyeing, the greater the thermal migration of the dye, and the more serious the effect on the color and fastness of the dyed product. Heat treatment below 130 ℃, the thermal migration of the dye is not great; heat treatment at 140 ℃ or even above 160 ℃, the thermal migration of disperse dyes is significantly increased. Because different disperse dyes have different thermal migration tendencies, the thermal migration of different disperse dyes is different when processed under the same dry heat condition. Therefore, the dyeing color matching formula should be reasonable, otherwise it will easily lead to changes in the color of the dyed product.

(3) The relationship between heat treatment time and thermal migration

The heat treatment (baking) time at the temperature of 180℃ is in the range of 20-40s. With the extension of time, the migration of the dye increases sharply; in the range of 40-50s, the thermal migration of the dye does not increase significantly; over 60s, low temperature and medium temperature On the contrary, the thermal migration of type disperse dyes decreases.

(4) The relationship between dye sublimation and thermal migration

There is a certain connection between the thermal sublimation and thermal migration of disperse dyes. It is imprecise to simply understand the thermal migration of dyes as thermal sublimation. Production practice has proved that some high-temperature dyes with good sublimation resistance have low thermal migration (such as disperse gray S-BN), and some have high thermal migration (such as disperse red S-3GFL, disperse dark blue HGL, etc.) ; Some low-temperature and medium-temperature dyes with poor sublimation resistance (such as Disperse Red B, Furong Brilliant Red E-RLN, etc.), based on the results of parallel determination, have little thermal migration.

Of course, the initiation temperature of the thermal migration of disperse dyes has a certain relationship with the sublimation resistance of the dye itself, that is, as the sublimation resistance of the dye increases, the initiation temperature of the thermal migration also increases accordingly. For example, the temperature of low-energy disperse dyes is around 130℃, the temperature of medium-energy dyes is around 135-140℃, and the temperature of high-temperature dyes is around 140-145℃.