What is the sun-light fastness of dyes?

In the process of photochemical changes, the color system of the dye molecules changes or is damaged, and the color change or fading will occur. In the field of textiles, the light resistance of dyes is represented by daily sun exposure, or it is also called optical resistance.

Due to the different intensity of different light sources under different wavelengths, the larvae lights are the closest to the sunlight. Therefore, it is generally used to simulate the sunlight and test the exposure accuracy.

The application of sun exposure accuracy testing and national European, American, American and Japanese test methods

1. Applicable situation of sun-light fastness testing

In China, the same as soap is washing color, the sun exposure is not included in GB 18401, but it is also widely included in various clothing standards.

However, in the specific implementation, unless it is some outdoor clothing brands, ordinary fashion and clothing brand companies attach great importance to the accuracy of sun exposure. There is not much time for outdoor sun exposure, and soap washing occurs at high probability and high frequency. Therefore, the effect of sun exposure on clothing quality is much lower than the impact of soap color washing.

In foreign countries, the sun exposure is also a criterion for negotiation like soap -washing color.

2. The four standard methods of Europe, Japan and the United States

GB sun exposure is divided into 8 levels, the lowest level is the lowest, and level 8 is the highest. Each level is dyed in a certain concentration of blue fabric samples with a specified dye.

The method of GB/T 8427 is the MOD European standard ISO 105-B02: 2014, which is basically the same. All use the method of exposed to standard wool fabrics to expose the samples with the target level N blue wool and N-2 and N-2 levels. The blue wool is exposed together until the first stage of the target blue wool standard is equal to the color -changing gray card level 4, that is, stop exposure, cover the first stage, and continue to expose the second stage until the target blue wool Sample samples are equal to the color -changing gray card level 3, stop exposure. After dyeing, the sample will be exposed to the color difference with the blue woolen label sample, and each stage corresponds to each stage, and the number of levels will be evaluated.

The method of the AATCC 16E in the US standard is more commonly used. After the exposure counter on the sun testing device is determined to meet the AFU amount required by the guest (generally 20), that is, the termination of the color change rating.