The main functions of light stabilizers are: shielding light, absorbing and transferring light energy, quenching or capturing free radicals. Light stabilizers are generally divided into four categories based on their mechanism of action: light shielding agents, ultraviolet absorbers, quenchers, and hindered amine light stabilizers.

Hindered amine light stabilizers (HALS) are a class of organic amine compounds with steric hindrance effects. Due to their ability to decompose hydrogen peroxides, quench reactive oxygen species, capture free radicals, and effectively regenerate functional groups, HALS is the most widely used type of light stabilizer both domestically and internationally. The consumption of hindered amine light stabilizers in China accounts for about 65% of the total domestic consumption of light stabilizers. UV absorbing light stabilizers, commonly known as UV absorbers, utilize their molecular structure to convert light energy into heat energy, thereby preventing plastic materials from undergoing photo oxidation reactions and achieving photo stabilization. UV absorbers are classified into benzophenones and benzotriazoles based on their molecular structures. The consumption of benzophenone light stabilizers and benzotriazole light stabilizers in China accounts for about 25% and 10% of the total domestic consumption of light stabilizers, respectively.

Both quenchers and UV absorbers achieve photostability by transferring light energy. UV absorbers transfer energy when their own molecules directly absorb light energy, while quenchers interact with high-energy and highly reactive excited functional groups in plastic materials due to light exposure, transferring the energy of excited functional groups. It is precisely because the quencher transfers energy with the ultraviolet absorber.

The mechanism of quantity is completely different, and quenchers are listed as one of the four major series of light stabilizers. The industrial product of quenchers is the complex of divalent nickel, which contains heavy metal nickel in its molecules. From the perspective of protecting the environment and human health, developed countries and regions such as Europe, North America, and Japan have stopped or restricted the use of quenchers. There is only one quenching agent production plant in China, which produced only over ten tons of products in 2003. From the analysis of the application status of quenching agents both domestically and internationally, quenching agents as industrial light stabilizers will disappear from the international and domestic markets. At that time, quenchers can only coexist with hindered amines, UV absorbers, and light shielding agents in books for a long time.

Light shielding agents include carbon black, titanium dioxide, zinc oxide, etc. The industrial application of nanotechnology will significantly improve the light and weather resistance of light shielding agents in plastic materials.

Three types of light stabilizers, namely light shielding agents, ultraviolet absorbers, and quenchers, were industrialized in China around the 1960s. However, hindered amine light stabilizers, although only began industrial production in the mid-1970s, have seen a much faster increase in product variety and output compared to the other three types of light stabilizers, making them a rising star in the plastic light stabilizer family.