Pretreatment of textile fabric

Pretreatment of textile fabric

Pretreatment of textile fabric mainly refers to the removal of impurity for fiber and textile. It is aimed to improve whiteness and performances such as softness of the textile. Fiber performance, impurity's component and textile method should be considered in the treatment process

The purpose of pretreatment of textile fabric

Pretreatment of textiles, which is going through chemical and physical mechanical action, is a procedure to remove the natural impurities contained in the fiber, slurry and oil applied in the process of textile processing.It can make fiber get excellent quality andthe fabric have white appearance, soft feeling and good permeability. In this way, textile gets a chance to meet requirements and provide qualified semi-products for dyeing, printing and finishing.

The process of pretreatment of textile fabric

The pretreatment process varies with the quality of the fiber, the process of textile processing, the post-process and the quality of the finished products.

Original cloth preparation - burning wool - desizing - bleaching - open - rolling - rolling - drying - mercerizing

Common quality problems appeared in pretreatment of textile fabric

1. First, the problem of whiteness and poor performance

Poor white degree including impurity and in homogeneity. These are related to the quality of the knitted fabric.For example,low-level cotton content often causes impure whiteness and poor performance. While the most critical factors are the process formulation and the selection of additives.

2. The cottonseed shells are not removed completely

The removal of cotton seed mainly goes in with NaOH. Under certain conditions,  NaOH can cause the expansion and swelling of the cotton seed shells. Incomplete elimination mainly caused by insufficient temperature and time. Therefore complete removal must go in with proper temperature and adequate time. H2O2 and there finishing agent play a positive role in removing cottonseed shells. In a word, certain temperature and adequate timeisneeded to ensure the removal, NaHSO3 or anthraquinones can be added at the same time, it can help a little.

3. Holes and tendering

Besides the original holes and singeing holes, the main reason for the hole and brittle damage is that there are metal ions such as Fe3 + and Cu2 + in the cloth or the bleaching bath of H2O2. These metal ions catalyze the rapid decomposition of H2O2, resulting in brittle fiber. If the metal ions,(such as rust, etc.) concentrate at one point, the fiber, yarn will tender to form a hole, so high quality oxygen bleaching stabilizer and chelating dispersant should be added in H2O2 bleaching. They can complex and absorb metal ions in the fabric and bleaching bath so that they can prevent tendering caused by the fast decomposition of H2O2.

Of course, cloth with alkali or acid  an also cause tendering. At the same time, in the case of cloth with alkali in high temperature, the fabric can tender when the air present in the fabric. It can be prevented by adding the weak reducer such as NaHSO3. In addition, the dampness of the fabric is also one of the reasons for the fragile and broken holes.