Light Stabilizer Mechanisms and How Light Damages Plastics

Causes of light damage to plastics: for most plastics, the sensitive wavelength most likely to cause damage lies between 290 and 400 nm, which is exactly the ultraviolet region. The energy of ultraviolet light can break the chemical bonds of polymers, triggering photo-oxidation or oxidative photodegradation, causing deterioration of physical and mechanical properties. At the same time, the formation of carbonyl decomposition products and chromophores deepens the color change.

　　Mechanisms of light stabilizers:

　　(1) Light screening agents: absorb or reflect ultraviolet light so that light cannot shine directly into the interior of the polymer, thereby effectively inhibiting photo-aging. Examples: TiO₂, ZnO.

　　(2) UV absorbers: strongly absorb ultraviolet light and convert its energy into harmless heat. Examples: benzophenones, benzotriazoles.

　　(3) Quenchers: can eliminate the excitation energy from excited polymer molecules, returning them to a low-energy state. Mainly metal complexes.

　　(4) Free-radical scavengers: capture different free radicals, thereby preventing or delaying the photo-degradation process. Example: hindered amines.

　　Principles for selecting light stabilizers: they must effectively eliminate or weaken the destructive effect of ultraviolet light on polymers without affecting other properties of the polymer; they must have good compatibility with the polymer, be non-volatile, non-migrating, and not be extracted by water or solvents; they must have low absorption of visible light, be non-coloring and non-discoloring; and their color must be close to that of the polymer, so that adding them does not change the polymer's color.

Beijing Tiangang Auxiliary Co., Ltd. is a national-level high-tech enterprise focused on the R&D and production of high-performance polymer additives. It is one of the earliest enterprises in China specialized in the development and production of anti-aging functional materials. Tiangang's products enjoy a high reputation in both domestic and international markets, lead in key markets, and are exported to many major countries and regions in Europe, North America and Asia, and are selected by numerous internationally renowned enterprises.

　　The company has more than 400 employees and owns two modern production bases in Daxing District, Beijing (60,000 m², 100 mu) and Gu'an County, Hebei Province (100,000 m², 150 mu). In particular, the newly commissioned Gu'an plant, designedlight stabilizerwith an annual capacity of 10,000 tonnes, is currently one of the larger integrated light stabilizer production bases in Asia. With advanced production process technology and full implementation of DCS automated production management, it ensures excellent product quality through lean management.