The role of ultraviolet absorbent

Uv absorber is a kind of light stabilizer, which can absorb the ultraviolet part of sunlight and fluorescent light source without changing itself.  

Because the sun contains a lot of uv light harmful to colored objects, its wavelength is about 290-460 nanometers, these harmful UV light through chemical Redox reaction, so that the color molecules finally decompose and fade.  

There are both physical and chemical ways to prevent color damage from harmful ultraviolet light.  

Here is a brief introduction to chemical methods, that is, the use of ultraviolet absorbent to protect the object to implement effective prevention, or weaken its damage to color.  

Uv absorbers should have the following conditions  

(1) Can strongly absorb ultraviolet (especially the wavelength of 290-400nm);  (2) Good thermal stability, even in the processing will not change due to heat, thermal volatility is small;  (3) Good chemical stability, no adverse reaction with the material components of the product;  (4) good miscibility, can be evenly dispersed in the material, no frost, no seepage;  The absorbent itself has good photochemical stability, does not decompose, does not change color;  ⑥ Colorless, non-toxic, odorless;  ⑦ Immersion resistance;  ⑧ Cheap and easily available;  9. Insoluble or insoluble in water.  

Uv absorbers can be divided into the following categories according to their chemical structure: salicylate, benzenone, benzotriazole, substituted acrylonitrile, triazines and blocked amines.