How to rate color fastness? Most of the current test methods for color fastness are simulated test or comprehensive test according to the environment and conditions, and the fastness grade is evaluated according to the discoloration of samples after test and/or the staining of the lining fabric.

In the color fastness rating, it is necessary to comprehensively assess the changes of the three properties of color, that is, the changes of hue, lightness and purity.

Hue: Hue refers to the appearance of color. Among the three attributes, hue can be used to distinguish colors. According to the different wavelength of light, color has the properties of red, yellow or green, which is called hue.

Two, brightness: according to the degree of reflected light on the surface of the object, the degree of brightness of the color will be different, the degree of brightness of the color is called brightness.

Three, purity: purity refers to the saturation degree of color, the more pure the wavelength of light, the higher the hue purity, and the lower the purity.

Have you ever had a color fastness problem? How to deal with this situation?

1. Colour fastness to water, perspiration and soap washing

1) Common problems

Stain is not up to standard

2) How to improve

Improve fabric dyeing performance, such as dyeability, solid color, strengthen soap washing, reduction cleaning, fully remove floating color.

2. Color fastness to sun

1) Unqualified factors

The structure of fabric

Molecular structure of dye

Use dye with different color fastness to the sun

2) How to improve

Correct selection of dyes, formulation and implementation of reasonable dyeing process conditions, so that the fabric dyed evenly, fully fixed color; Strengthen to avoid the adverse effects of post-finishing soaping and washing after dyeing, fully remove floating color.

3. Phenolic yellowing

1) Common problems

White fabrics sometimes turn yellow in storage. The yellow parts disappear and return to their original white color after acid treatment. If lye is dropped again, the yellow color will return. The main reason is phenolic yellowing.

2) How to improve

Use packing materials without BHT, such as PE film, wrapping paper and carton.

Cloth processing storage place to avoid air pollution, fluorescent whitening agent treatment (to consider the fluorescent whitening agent acid resistance, alkali stability).