There are many varieties of optical brightener agents, and there are certain brands of whitening agents for the whitening of various fibers.Although the chemical structure and properties of various brighteners are different, the principle of brightening fibers or fabrics is the same.
The principle of whitening is mainly due to the conjugated double bond system in the molecule of the whitening agent, which has good planarity. This special molecular structure can absorb ultraviolet rays (wavelength 300 ~ 400nm) in sunlight under sunlight. The blue-violet light (wavelength is 420～500 nm), the blue-violet light mixes with the yellow light on the fiber or fabric to become white light, which makes the fiber or fabric obviously white.
The brightening effect of optical brightener is only optical brightening and supplementing color, and can not replace chemical bleaching. Therefore, if the fabric without bleaching is directly used for whitening with fluorescent whitening agent, the whitening effect is not ideal. From the principle of the fluorescent whitening agent, the whitening effect of the whitening agent mainly depends on the content of ultraviolet rays in the sunlight and the concentration of the fluorescent whitening agent on the fiber or fabric.