How To Improving dye fastness to sunlight ?

About fastness to sunlight:

Light fastness refers to the ability of dyes to maintain their original color under sunlight. According to general regulations, the determination of light fastness is based on sunlight. In order to facilitate control in the laboratory, artificial light sources are generally used and corrected if necessary. The most commonly used artificial light source is the hernia light, but also the carbon arc lamp. When the dye is irradiated with light, the dye absorbs light energy, the energy level is increased, the molecule is in an excited state, and the color system of the dye molecule changes or is destroyed, causing the dye to decompose and discolor or fade.

Method for improving dye fastness to sunlight

1. Improve the structure of the dye so that it can consume light energy while minimizing the influence of the dye color system, so as to maintain the original color; that is, the dye with high sun fastness is often said. The price of such dyes is generally higher than that of ordinary dyes. For fabrics with high sun exposure, the dyes should be selected first.

2. If the fabric has been dyed and the fastness to sunlight cannot be achieved, it can also be improved by additives. Add appropriate additives during or after the dyeing process to make it react with light before the dye when it is exposed to light, which consumes light energy, thereby protecting the dye molecules. Generally divided into ultraviolet absorbers and anti-ultraviolet agents, collectively referred to as sun light fastness enhancers.