How many grades of color fastness to light should be considered a standard?

With the continuous increase of export business, the various indicators of the product must meet the international requirements, and the light fastness has become the most difficult indicator among the various indicators. Especially for products exported to Japan and the European Union, many light fastnesses do not meet the standard. Some people only require samples to meet the standard, and large products can be ignored. In this way, we tried every means (such as using high-sunlight dyes, adding light fastness improver, and conducting temporary methods such as ultraviolet irradiation of samples before testing, etc.) to make the samples reach the standard. However, once the bulk test fails, there is a risk of returning the product and claiming a claim. So how many levels of sun exposure should be considered a standard?

First of all, we must understand what light fastness is. Light fastness refers to the degree of light fastness of dyed fabrics, that is, the degree of fading and discoloration of dyed fabrics under sunlight or artificial light sources. Sun fading is a relatively complicated process. Under the irradiation of light, dyes absorb light energy, and molecules decompose or rearrange to cause fading and discoloration. The fading mechanism is different. For example, the fading of azo dyes on cellulose fibers is mainly the result of the dye being oxidized by air under the irradiation of light, while its fading on protein fibers is often the result of reduction. The test method can be exposed to sunlight or exposed to a sunlight machine. The fading degree of the sample after exposure is compared with the standard color sample. There are two rating standards: wool blue label and gray card. The American Standard is divided into 5 grades, with 5 being the best and 1 being the worst. Fabrics with poor light fastness should not be exposed to the sun for a long time, and should be dried in the shade in a ventilated place. Generally, the xenon lamp is used for 24-hour testing. Therefore, it is generally required to reach level 3~4 to be regarded as the standard and to meet the wearing needs.

Light fastness improver JV-903 is a benzotriazole anti-ultraviolet finishing agent, which can significantly improve the anti-ultraviolet grade, light fastness to light and perspiration of reactive, direct, disperse, acid and vat dyed fabrics . It is suitable for improving the anti-ultraviolet finishing of fabrics dyed with reactive, direct, disperse, acid and vat dyes.

Main performance:

Significantly improve the UV resistance, sunlight and perspiration light fastness of fabrics dyed with reactive, direct, disperse, acid and vat dyes; it is suitable for all kinds of natural fibers and synthetic fibers; it can be finished in the same bath as the dyeing process, and the treatment process The color shade of medium-dyed fabrics has little effect; it has certain washability.