Harm of UV
Ultraviolet rays directly irradiate the skin, in addition to having a bactericidal effect, it also has the functions of adjusting and improving nerves, endocrine, digestion, circulation, breathing, blood, immune system and promoting the production of vitamin D. However, in recent years, people have gradually realized that excessive ultraviolet rays cause photochemical reactions, which can cause a series of changes in human body functions, especially harm the human skin, eyes, and immune system.
The benefits of simulated plants
The reason why artificial plants can resist ultraviolet rays is mainly that ultraviolet absorbers are added to the production materials. Generally, ultraviolet absorbers are not added in a year, so that they will be discolored. If they are added, they will not fade for 3-5 years, that is, The anti-ultraviolet absorber has been consumed. Ultraviolet absorber has the function of absorbing ultraviolet rays, good thermal stability, etc.
UV absorber
Ultraviolet absorber is a kind of light stabilizer, which can absorb the ultraviolet part of sunlight and fluorescent light source without changing itself. Under sunlight and fluorescence, plastics and other high-molecular materials produce auto-oxidation reactions due to the action of ultraviolet rays, which leads to degradation and deterioration of polymers, which deteriorates appearance and mechanical properties. After adding the ultraviolet absorber, this high-energy ultraviolet can be selectively absorbed to make it into harmless energy to be released or consumed.
Ultraviolet absorbers are mostly aromatic compounds containing benzene rings. They can absorb ultraviolet rays. The absorber absorbs the energy of ultraviolet rays due to the resonance of the benzene ring. It is converted into heat or non-destructive light energy and is released. Then it returns to the original molecular structure. In this way, the absorbent can be used repeatedly. It will not damage the absorbent itself. It is a chemical anti-ultraviolet principle.
Different types of polymers have different wavelengths of ultraviolet rays that degrade them. Different ultraviolet absorbers can absorb different wavelengths of ultraviolet rays. When used, the ultraviolet absorber should be selected according to the type of polymer.
The ultraviolet absorber should have the following conditions: ①It can absorb ultraviolet ray strongly (especially the wavelength is 290-400nm); ②Good thermal stability, it will not change due to heat even during processing, and the thermal volatility is small; ③Chemical stability Good performance, does not adversely react with the material components in the product; ④ Good miscibility, can be evenly dispersed in the material, no blooming, no exudation; ⑤ The absorber itself has good photochemical stability, does not decompose, and does not change color ⑥Colorless, non-toxic, odorless; ⑦Dipping resistant
