1. The role of deepening agent for spinning and dyeing
Deepening agent is a kind of spinning and dyeing auxiliary used to improve the dyeing depth of disperse dyestuff on polyester fabric. According to the use of different methods, as well as the order of spinning and dyeing, deepening agent can be divided into：
①Deepening agent used in the dyeing process.
②Deepening agent used after dyeing.
(1) Deepening agent used in the dyeing process
In order to improve the dyeing rate and color fixing rate of fiber or increase the affinity of coating to fiber, deepening agents are often used in the dyeing process.
Adding deepening agent in the dyeing and finishing process can not only effectively improve the dyeing effect of fibers and modify the surface of fibers, thus changing (improving) the surface properties of textile fibers, increasing the affinity of fibers for dyes, making dyes better absorbed and fixed by fibers, but also reduce the amount of dyes, reduce the degree of pollution of waste water, etc.
(2) Deepening agent used in finishing after dyeing
In the process of dyeing and finishing, due to the differences in nature of the fiber, dyeing conditions (temperature, dye concentration, etc.), there are differences in the color of the dyed fiber. Especially in the dyeing and finishing process, the color differences will be more obvious.
Therefore, the deepening agent is usually used to correct the color of this series of color difference fabrics in wet finishing after dyeing. And its operability and effect are better.
The use of deepening agent not only can give the fiber better affinity, dye absorption, reduce the use of dye and waste, but also bring better results to the fabric.
2. What are the applications of chelating agents in the printing and dyeing industry?
Chelating dispersant is one of the textile printing and dyeing auxiliaries, belongs to a highly efficient, multi-purpose organic chelate. It plays a very big role in the textile printing and dyeing industry. Let us take you to understand the application of chelating dispersant in the textile printing and dyeing industry.
(1) Water treatment: chelating dispersant has the effect of softening water quality. Chelate dispersant in the process of water softening treatment can remove the metal ions in the water, and also can decompose hard water flocculent.
(2) Desizing: usually textiles are sized with heavy metal compounds as textile auxiliaries in the sizing stock, such as zinc salts, cuso4, organic copper-containing compounds, etc.; but these compounds are not conducive to enzyme desizing, so adding chelating dispersant can make the pulp easier to expand, detach from the fiber, as well as the decomposition and removal of colloidal-like. Besides, it can prevent impurities and pulp from settling on the fiber again. The addition of chelating dispersant when desizing can make the backing whiter and the desizing safer.
(3) Bleaching: metal ions contained on the fiber, metal ions in the un-softened water, Fe3+ in the equipment pipeline, etc., will increase the content of iron ions and so on in the bleaching solution. Adding chelating agent can effectively block metal ions and indirectly control the decomposition rate of hydrogen peroxide to prevent damage to the fabric.
(4) Polyester alkali reduction: adding chelating dispersant can effectively prevent the accumulation of debris from polluting the equipment.
(5) Soaping: soaping with an appropriate amount of chelating dispersant can make the floating color on the surface of the printed and dyed fabric completely removed, so that the fabric gets better dyeing fastness.
(6) Color stripping: when the fabric dyeing does not match or uneven dye needs to be stripped, adding the right amount of chelating dispersant is conducive to fabric stripping, so as to achieve a better restoring effect, etc.