Now using a high temperature and high pressure dyeing method with better quality, in order to prevent the appearance of color flowers, color spots and other dyeing defects in the dyeing process, we must pay attention to the following aspects:

01 Choice of dye

Disperse dyes are difficult to dye polyester fibers at low or normal temperature, and only when the glass transition temperature of polyester is exceeded, dyes are quickly dyed. If the initial dyeing rate of the selected several color matching dyes is too large, it is easy to form local competition at this time and cause color flowers. Therefore, when selecting dyes, the initial dyeing rate of several matching dyes should be similar, in addition, if the initial dyeing rate of the selected dyes is high, it is easy to cause color flowers. In general, when dyeing polyester with disperse materials, dyes with close initial dyeing rate, slow initial dyeing rate, good quality and similar color compatibility should be selected. Such as light color with E type, medium color with SE type, dark color with XF, SF type are basically able to polyester deep medium light dyeing, and the effect is good.

02 Selection of auxiliaries

Dispersant also has great influence on polyester high temperature and high pressure dyeing, because different dispersant HBL value is different, the dispersant ability is also different. Because the dyeing temperature of disperse dye on polyester is 80-100 ° C, the dispersant is required to have a high dispersion ability, that is, the HBL value is high and the turbidity point is above 100 ° C. The practice of major dyeing plants has proved that anionic dispersants and non-anionic dispersants have higher turbidity points and are ideal dispersants.

03 Control of heating rateThe heating rate is also an important factor in the production of color flowers, after reaching the glass transition temperature of polyester, the temperature is too fast, the dye will quickly dye the fiber, forming a local dye and resulting in color flowers and color blocks, if the initial dyeing rate of the dye is high, the color flower is more serious. Therefore, in the process of dyeing temperature rise, it can be divided into three stages with different temperature rise rates to control.

The first stage of Di is to rise from normal temperature to 75℃, and the disperse dyes in this stage will hardly dye the fibers, which can be used at a faster heating rate of 2-3℃.

The second stage is 75-110℃, this temperature zone is the fastest stage of dye dyeing, must use slow temperature rise, control at 0.8-1℃ is appropriate,

The third stage is 110-130 ° C, at this stage the dye will be exhausted, and the temperature rise rate can be 1.5-2 ° C.

04 Other factors

For example, chemical material, cloth volume, bath ratio, PH value, whether the blank cloth is clean, whether the liquid flow speed is appropriate, fabric running speed and other aspects also have a certain impact on the production of color flowers, dispersion material is generally used 40℃ warm water chemical material, stirring evenly before injection into the dye tank; The amount of dyeing should not exceed the maximum capacity of the dyeing tank; The bath ratio of 1:8-12 is more suitable. The PH value should be controlled at 4-4.5; When dyeing, the cloth surface should be clean and the PH value should be neutral. In addition, it is necessary to reasonably adjust the flow speed and the running speed of the fabric in the cylinder.

Finally, if there is a slight color flower after the end of dyeing, a certain amount of repair agent can be added to repair the color by the method of shifting dyeing.

Reprinted: Yibu network