(1) Light shielding agents: These are substances that can shield or reflect ultraviolet rays, preventing light from penetrating into the interior of polymers, thereby protecting polymers. Light shielding agents include inorganic pigments such as carbon black and titanium oxide and organic pigments such as phthalocyanine blue and phthalocyanine green, among which carbon black has the best shielding Effekt .
(2) Ultraviolet absorbers: They can effectively absorb ultraviolet rays with a wavelength of 290~410nm, but rarely absorb visible light. They have good thermal stability and light stability. According to their chemical structure, they can be mainly divided into: o-hydroxybenzophenone, benzotriazole, salicylate, Triazin och substituerad akrylonitril . De används tillsammans som extra ljusstabilisatorer och hindrade lätta stabilisatorer, särskilt i polyolefiner eller beläggningar .}
(3) Quenchers: They can accept the energy absorbed by the chromophore in the plastic and dissipate the energy in the form of heat, fluorescence or phosphorescence, thereby protecting the polymer from damage by ultraviolet rays. They have a good stabilizing effect on polymers and are mostly used in films and fibers. Mainly some divalent organic nickel Chelates . Organiska nickelljusstabilisatorer har goda prestanda, men på grund av toxiciteten hos tungmetalljoner kan de ersättas av andra icke-toxiska eller låg-toxiska släckare .}
(4) Free radical scavengers: This type of light stabilizer can capture active free radicals generated in polymers, thereby inhibiting the photooxidation process and achieving the purpose of light stabilization. Mainly hindered amine light stabilizers (HALS). It is the most promising new type of high-efficiency light stabilizer, with an average annual demand growth rate of 20% ~ 30% internationellt .
(5) Hydroperoxide decomposer: It is a type of hindered amine light stabilizer. Polymers can produce hydroperoxides during storage and processing, leading to photooxidative degradation of polymers. Hydroperoxide decomposers can decompose peroxides to generate stable nitrogen-oxygen free radicals and further capture free radicals, thereby inhibiting polymernedbrytning .