What is an ultraviolet absorber?

　　Ultraviolet absorber is a light stabilizer that can absorb ultraviolet light in sunlight and fluorescent light sources without changing itself. Under sunlight and fluorescence, plastics and other high-molecular materials produce automatic oxidation reactions due to the action of ultraviolet rays, which leads to the degradation and degradation of polymers, which deteriorate the appearance and mechanical properties. Adding UV absorber can selectively absorb this high-energy UV, making it harmless energy to release or consume.

　　Different types of polymers make the degradation of ultraviolet wavelengths different. Different ultraviolet absorbers can absorb different wavelengths of ultraviolet light. When using, the ultraviolet absorber should be selected according to the type of polymer.

　　The ultraviolet absorber should have the following conditions: ① can absorb ultraviolet light strongly (especially the wavelength is 290-400nm); ② good thermal stability, even during processing will not change due to heat, thermal volatility is small; ③ chemical stability Good performance, no adverse reaction with the material components in the product; ④ Good miscibility, can be evenly dispersed in the material, no frost, no ooze; ⑤ The absorber itself has good photochemical stability, does not decompose, does not change color ; ⑥ colorless, non-toxic, odorless; ⑦ resistant to immersion; ⑧ cheap and easily available. According to the chemical structure, ultraviolet absorbers can be divided into the following categories: salicylates, benzophenones, benzotriazoles, substituted acrylonitriles, triazines and others.

　　Ultraviolet absorbers are used in plastics, paints, dyes, car windshields, cosmetics, medicines, sunscreens, etc.