How is color fastness rated? Most of the current color fastness test methods are simulated tests or comprehensive tests according to the environment and conditions of the action, and the fastness grades are evaluated according to the discoloration of the samples after the test and (or) the staining of the lining fabric.
In the rating of color fastness, it is necessary to comprehensively evaluate the changes of the three attributes of color, that is, the changes of hue, lightness and purity.
1. Hue: Hue refers to the appearance of a color. Among the three attributes, hue can be used to distinguish colors. According to different wavelengths of light, colors have properties such as red, yellow or green, which are called hues.
2. Brightness: According to the degree of reflection of light on the surface of the object, the degree of light and shade of the color will be different. The degree of light and shade of this color is called brightness.
3. Purity: Purity refers to the degree of saturation of the color. The simpler the wavelength of the light wave, the higher the hue purity, and vice versa.
1. Color fastness to water, perspiration and (soap) washing
1) FAQ
Staining is not up to standard
2) How to improve
Improve the dyeing performance of fabrics, such as dye penetration, full color fixation, strengthen soaping and water washing, reduction cleaning, and fully remove floating color.
2. Color fastness to sunlight
1) Unqualified factors
The structure of the fabric
Molecular structure of dyes
Color matching with dyes with different light fastnesses
2) How to improve
Correctly select dyes, formulate and implement reasonable dyeing process conditions, so that the fabric is dyed level and fully dyed, and the color is fully fixed; strengthen to avoid the adverse effects of post-finishing, soaping and washing after dyeing, and fully remove floating color.
3. Phenolic yellowing
1) FAQ
White fabrics sometimes turn yellow during storage, and the yellowish part disappears and returns to the original white after acid treatment, and returns to yellow if lye is added again. The reason is mainly phenolic yellowing.
2) How to improve
Use BHT-free packaging materials such as PE film, wrapping paper and cartons.
Cloth processing and storage sites should avoid air pollution, fluorescent whitening agent treatment (the acid resistance and alkali stability of fluorescent whitening agent should be considered), etc.
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