Ultraviolet absorber  is a very important additive in plastic products. It is a stabilizer that plays a light-stabilizing role. It mainly produces a stabilization effect by absorbing and converting the destructive ultraviolet part of sunlight. UV absorbers  are mainly used in plastic products, such as plates, cables, pipes and other thick products. In many cases, UV absorbers  are also added to plastic films to inhibit or delay the negative effects of UV light on the protected items or substances effect.

We all know that the electromagnetic waves emitted from the sun are very broad, and the ones that can reach the ground mainly include ultraviolet, visible and infrared rays. The energy of radiation is inversely proportional to the wavelength, the shorter the wavelength, the greater the energy. Among them, ultraviolet rays in the wavelength range of 290nm-400nm have the shortest wavelength and the highest energy, and are also the most destructive to polymers such as plastics. The bond energy of organic polymers is usually in the range of 290~400kJ/mol, so it is easy to be ultraviolet destroyed. Therefore, ultraviolet light is the main factor affecting the photo aging of plastics. But it should be noted that the sensitivity of different structures of polymer compounds to different wavelengths of ultraviolet light is different.

The reason why polymer materials such as plastics have many excellent properties is due to their long enough macromolecular chains, but due to the short wavelength of ultraviolet rays and high energy, under the action of ultraviolet rays (most of which also involve oxygen), polymer materials absorb After ultraviolet light, it is easy to form an electronic excited state, and the molecules of this excited state can cause a series of photochemical reactions, that is, free radical chain reaction, and at the same time, accompanied by oxidation, "photo-oxidative aging" or "photo-oxidation reaction" occurs. The macromolecular chain of the polymer is cut or a certain cross-linking occurs, which directly affects the performance of the polymer material, so a series of aging phenomena appear. Such as darkening, brittleness, hardening, surface cracking, and decline in mechanical and electrical properties, etc., which eventually loses its use value.