A Brief Discussion on the Development of Hindered-Amine Light Stabilizers

Hindered amine light stabilizers (HALS) are a class of high-efficiency stabilizers that appeared in the mid-1970s to protect polymers such as plastics and rubber against ageing. Their stabilizing effect is 2-4 times that of conventional absorptive light stabilizers, they are highly compatible with many resins, and they are the fastest-growing class of stabilizers today [1-2]. Worldwide, annual consumption of HALS is growing at 20%-30% and now accounts for 44% of total stabilizer consumption, ranking first among all stabilizer classes. For several decades HALS have remained a very active field of research, with new products appearing continuously. High-molecular-weight HALS are non-toxic and non-polluting and can be used directly in food packaging: Tinuvin 622, Chimassorb 944 and Cyasorb UV-3346 have all been approved by the U.S. Food and Drug Administration (FDA) for use in food-contact materials. Monomeric high-molecular-weight HALS such as Ciba-Geigy Chimassorb 119 and Chimassorb 2020, and the G and IV-628 grades developed by the Shanxi Provincial Institute of Chemical Engineering, are mainly used where weathering demands are high and offer excellent overall performance [3-5].
Since the 1990s, with the development of anti-thermal-oxidation functions, hindered-amine light stabilizers have found new application fields.