Application of buffer in fabric dyeing

Details:

Biological buffer has the function of pH maintenance of buffer system. It is mainly used in biochemical experiments and diagnostic detection. In addition, buffer is also widely used in industry, such as coatings, dyes, etc. This paper introduces the application of buffer in plant dyeing.

Many dyes are sensitive to the pH value of the dyeing bath. If the pH value of the dyeing bath is controlled carelessly, there will be dyeing defects such as light color, color difference, color flower and so on. In order to solve the above problems, it is necessary to add appropriate buffer to the dye solution of the dye bath to keep the pH value of the dye solution stable.

Buffer for fabric dyeing

Factors for adjusting pH with buffer for fabric dyeing:

1. The fabric is not cleaned thoroughly in the pretreatment process, resulting in a small amount of acidic or alkaline substances brought to the dyeing bath to change its pH value.

2. Some additives and auxiliaries in the dyeing process are not neutral, which will affect the pH value of the dyeing bath.

3. The pH value of some dyes is too high or too low. If they are added to the dyeing bath, it will cause the pH value of the dyeing bath to change. For example, the pH value of some disperse dyes is 8.60, and some even reach 10.60.

4. When the boiler supplies gas, negative pressure occasionally occurs, which may suck the acidic or alkaline solution in other containers back into the steam pipe. When heating the dye bath, these substances are brought into it.

Taking polyester fabric dyed with disperse dyes in high temperature and high pressure overflow dyeing machine as an example. Because many disperse dyes are sensitive to the pH value of the dyeing bath, they get great color differences when dyeing at different pH values. Only when dyeing in a weakly acidic (pH = 5 ± 0.5) dyeing bath, the color is the most colorful and pure. In order to keep the pH value of the dyeing bath stable during dyeing, acetic acid and sodium acetate buffer solution can be prepared.

The pH value required for dyeing bath of disperse dyes, weak acid dyes of wool and reactive dyes is different. Different buffers are needed to strictly control the pH value of dyeing process. The pH value of dyeing bath is determined by dyeing depth and auxiliaries used for dyeing. Desheng is a biochemical buffer manufacturer, which can provide Tris, mops or other buffers required by customers.