When dyeing textiles, color difference is a headache and a helpless problem for dyeing masters. The color difference between the head and tail of the same vat, the color difference between the center and the edge, the vat difference and other color difference problems are annoying.

1. What is color difference:

The color depth of dyed textiles is different, and the color light is different.

1.1 Color difference in the same batch: In the same batch of products, there is a color difference between boxes and boxes, between pieces and pieces, between packages and packages, and between pieces of the same color number.

1.2 Color difference in the same piece: There is a color difference in the left and middle of the same piece of products, or there is a color difference between the front and back, or there is a color difference on the front and back. Color difference is one of the common and multiple defects in dyeing and finishing plants, which seriously affects the quality of the dyed products.

2. Causes of color difference

Different types of fabrics have different fiber compositions, different types of dyes and process equipment used in dyeing, and different requirements and characteristics in dyeing processing. The causes and manifestations of defects are different, and the dry cleaning and stain treatment methods are also different. There are many different appearances of color difference, but the main reasons are as follows.

2.1 Uneven distribution of dyes on fabrics in advance:

If the dyes are unevenly distributed on various parts of the fabric before fixation, color difference will inevitably occur after fixation. The main reasons for this phenomenon are:

2.1.2 Fabric factors: Due to different fiber properties or insufficient uniformity of pre-treatment such as retardation, boiling, bleaching, and silking, the permeability of semi-finished products before dyeing is uneven, resulting in differences in the degree of dye absorption.

2.1.2 Liquid absorption factors: Due to mechanical structural reasons or improper operation, the liquid carrying rate of various parts of the fabric is inconsistent, resulting in color difference. Uneven roller pressure and uneven addition of dyes and chemicals will cause uneven absorption of dyes by the fabric.

2.1.3 Pre-drying factors: During pre-drying after dipping in dye solution, due to inconsistent drying rates and degrees, the dyes migrate to different degrees, causing uneven distribution of dyes on the fabric.

2.2 Different fixation degree of dyes on fabrics:

Although the dyes are evenly distributed on the fabrics in the early stage, during the fixation process, if the conditions are not properly controlled (such as temperature, time, dye concentration, etc.), the dyes in some parts of the fabric are not fully fixed and are removed during the post-treatment soap washing, resulting in color difference. For example, inconsistent heat dissolution temperature of disperse dyes on both sides or front and back, insufficient partial reduction or oxidation of reduced dyes, poor steaming conditions of reactive dyes, etc. will cause color difference in the front and back or left and right of the fabric.

2.3 Dye color variation: This difference is not caused by uneven distribution of dyes on the fabric, but by some reasons that cause the color of some dyes on the fabric to change. Generally, there are the following reasons:

2.3.1 Pre-dyeing factors: uneven whiteness of semi-finished products or large differences in pH values ​​often cause color difference after dyeing.

2.3.2 Dyeing factors: For example, the heat dissolution temperature of disperse dyes is too high, which makes the color of some dyes darker; excessive reduction of reduced dyes can also cause color difference.

2.3.3 Post-dyeing factors: During the post-finishing process. For example, resin finishing, high temperature stretching and different pH values ​​on the fabric will cause the dye shade to change to varying degrees.

2.3.4 Soap washing: If the soap washing is not sufficient, the color will be insufficient and the shade will be inaccurate.