What are the basic functions and individual requirements of high temperature leveling agent

1. Basic functions of high temperature leveling agent

Hydrophobic disperse dyes are suitable for the dyeing of hydrophobic polyester fibers, but the hydrophobic nature of the dyes determines its low water solubility. This should be said to be a more contradictory thing in the dyeing process with water as the medium. For this reason, in commercial disperse dyes, a large amount of surfactants such as diffusing agents are blended in a proportion not lower than that of the dye. Generally dyestuff:filler=1:1~1.5. As a high-temperature leveling agent added in the dyeing bath, it also has certain auxiliary and supplementary functions to promote the suspension and diffusion of disperse dye particles in the dyeing bath and maintain a uniform and stable distribution. This is especially important for light and medium shades with a small amount of dyes, because the amount of light and medium shade dyes is correspondingly small, and the diffusing agent brought in from the dyes is also reduced simultaneously, and high-temperature leveling agents are necessary. provide some compensation.

The leveling of dyeing requires ideal retarding function, which is the key function that all leveling agents must have. However, for the level dyeing of polyester fibers, disperse dyes also need to cooperate with a strong migration function, because the dyeing of disperse dyes in polyester has no chemical reaction from beginning to end; and the compact structure of polyester fibers, and its extremely dense The characteristics of the surface crystalline layer play a key retarding role, and the dye migration can make up for the vacancy of the retardation in this aspect, especially after reaching the 130 ℃ insulation dyeing stage, the dyes in the dyebath have been overwhelming. After dyeing on the fiber, the slow dyeing function has basically completed its mission, and the dye migration function has become the main role at this stage, which can further promote and ensure the overall effect of the leveling agent.

Therefore, retardation, migration and diffusion are the most fundamental basic elements of high temperature leveling agents, and are also the basic functions that must be possessed in the use of various dyeing machines.

2. Analysis and classification of individual requirements

Different dyeing operation modes of different dyeing machines have also produced individualized special requirements for high-temperature leveling agents. In addition to the above basic necessary functions, special varieties with individual distinctions such as low-foaming type, anti-precipitation type, and penetration-enhancing type are also required to form a series.

①Low foam type and its applicability

For liquid flow, jet and other nozzle type loose fabric impregnation machines, the dye bath is vigorously agitated due to the rapid operation of the fabric in the liquid flow, jet and other dyeing machines. Especially in semi-filled dyeing machines, some auxiliaries and dyes are prone to foaming in this environmental condition. Leveling agents containing adducts of ethylene oxide are more prone to foaming. If the foam continues to increase and reaches a certain level, the nozzle will form a foamy air suction, which will reduce the spray pressure and eventually cause the grey fabric to stop. And once the rotation is stopped, it is very likely to produce color flowers, and wrinkle printing often occurs along with it. The longer the stoppage time, the more serious the consequences will be.

For this reason, the high-temperature leveling agent used in this type of dyeing machine should be a low-foaming type. Of course, in terms of subjective wishes, it is best to have no bubbles, but this does not conform to objective reality. The vigorous stirring of this type of dyeing machine from the beginning to the end is very beneficial to fully maintain the good suspension of the undissolved dyes in the dyeing bath. It is unrealistic and impossible to operate a bubble. Therefore, in semi-filled liquid flow and jet dyeing machines, it is still necessary to cooperate with the use of defoamer.

②Anti-precipitation type and its applicability

For the high temperature and high pressure jigger, the operation of grey fabric is mechanical transmission, and the amount of foam does not have much influence on the operation and effect of dyeing. However, the operating characteristics of this type of dyeing machine are that the cloth does not turn water, and the smaller bath ratio makes the unit concentration of dye g/l in the dye bath of the same color formula far greater than that of liquid flow, jet type and bobbin and loose fiber. Class dyeing machine (generally at least double).

These have correspondingly increased the objective conditions for the aggregation and precipitation of suspended dyes in the dyebath, so the probability of occurrence of color spot defects is far greater than that of dyeing machines equipped with powerful circulating pumps. Therefore, they especially need to use enhanced diffusion and anti-precipitation functional types, which are more suitable.

③ Penetration-enhanced type and its applicability

Packages, caged hanks, bulk fiber dyeing machines and other equipment are also equipped with circulating pumps with powerful pressure, but they are different from liquid jet dyeing machines in that the fibers are fully immersed in the dyeing bath, and It does not use nozzles, and neither the foam problem nor the anti-settling requirements are very acute.

However, they have the characteristics of the dyeing method that the water moves in the opposite direction of the jigger and the fibers do not move, and the fiber stack layer is much thicker than that of the liquid machine, jet machine, and jigger, which use single-layer grey cloth as the dyeing operation mode For example, including warp beam dyeing machines, in addition to the need for mechanical equipment to have sufficient water flow penetration ability, let the high temperature leveling agent supplement and strengthen the good penetration performance of all fiber layers in the inner, middle and outer layers. The leveling of the machine is both important and necessary. Therefore, for them, it is advisable to use a high-temperature leveling agent with enhanced penetration.