Factors Affecting Dyeing with High Temperature and High Pressure Dyeing Machine

1. Temperature
Temperature is the key factor of high temperature and high pressure dyeing machine. Increasing the temperature can increase the dye uptake of disperse dyes by%. However, when the temperature is above 130 ℃, the dye uptake of most disperse dyes no longer increases significantly. Too high temperature will cause hydrolysis of polyester ester bond, which will lead to decrease of elasticity and strength of the fiber and chromatic aberration. Therefore, high temperature and high pressure dyeing is generally limited to 145 degrees. Generally, the dyeing temperature is controlled between 125-130 degrees. When dyeing at this temperature, not only the levelness is good and the color yield is high, but also the PH value of the dyeing bath is controlled within the weak acid range of 5-6. Most disperse dyes are quite stable, so the color is very bright. In order to make the dye be evenly adsorbed by polyester, the heating rate must be strictly controlled. When the temperature rises to the specified temperature, the dye shall be kept warm for a period of time to ensure full diffusion and penetration of dye. Heat preservation dyeing time is generally 30-60 minutes, light color can be shorter, dark color can be longer. After dyeing, the temperature should not be lowered too fast, or it will affect the feel and cause creases.
2. PH value
Many disperse dyes will hydrolyze under high temperature and alkaline conditions, so it is appropriate to control acid conditions in high temperature and high pressure dyeing bath,
3. Application of additives
In high temperature and high pressure dyeing, in order to make the dye disperse stably in the dyeing bath and obtain leveling effect, appropriate dispersant and leveling agent can be added in the dyeing bath.