Hindered Amine Light Stabilizers (HALS) have attracted widespread attention since publication because of their excellent photostabilizing properties. Under the effect of heat, light and oxygen, Hindered amine functional group piperidine ring can be converted to the corresponding nitrogen oxygen radical, the nitrogen oxygen radical is very stable, and at the same time it can capture the alkyl radicals, alkoxy radicals in polymer, then generate the corresponding ester or peroxide ester. These generated esters and peroxides will continue to interact with alkyl radicals and alkoxy radicals in the material. In this way, HALS eliminates reactive radicals while regenerating nitrogen-oxygen radicals, thus greatly slowing down the aging of polymer materials.
Piperidine ring structure of traditional HALS
Due to the existence of the hindered piperidine structure, the alkalinity of the traditional HALS is high, and it is very easy to react with acid to form salt precipitation during processing and use, and reduce the generation rate of nitrogen-oxygen radicals, so that its photostabilizing performance is reduced, which limits its scope of application. In order to broaden the application of HALS, the development of low alkalinity HALS has become a hot R&D direction.
Currently, the main method is to change the substituents on the piperidine ring to alkyl (N-R) and alkoxy (NOR) substituents. As the presence of alkyl and alkoxy groups, acid groups are sterically hindered and cannot easily contact with active nitrogen, i.e., reduces the basicity. Research shows that the basicity of the HALS is: N-H>N-R>NOR.
Our N-R and NOR type low alkaline HALS can help you to solve the problem of light stability in acidic system, such as OMNISTAB LS119, OMNISTAB LS123, OMNISTAB LS8171, etc., which can be widely used in the field of plastics, automotive interior parts and coating modification.
v OMNISTAB LS119
Chemical structure of LS119
OMNISTAB LS119 belongs to the N-R type HALS, it has large molecular structure and particularly is suitable for all polymer materials requiring low volatility and high migration resistance. LS119 is widely used in agricultural films, coatings, adhesives, soft and hard PVC, polyurethane, polyamide fibers and other materials.
v OMNISTAB LS123
Chemical structure of LS123
OMNISTAB® LS123 is NOR type liquid HALS, shows weak alkalinity, which can avoid the reaction with acid components in coatings. It is widely used in automotive coating, industrial coating, decorative coating, and wood coating.
v OMNISTAB LS8171 (NOR371)
LS8171 is a NOR-type high molecular weight HALS, which provides light/heat stabilization of polymer materials and is particularly suitable for agricultural films, such as greenhouse and ground films. The recommended dosage is 0.2- 1.0%.
Its excellent light stabilizing effect will significantly extend the service life of agricultural films.
Even in the pesticides and soil disinfectants conditions, LS8171 also provides long-lasting stabilization.
In addition, LS8171 can be used in polyolefins (PP, PE) as well as in olefin polymers (EVA, EBA) when combined with OMNISTAB UV absorbers (e.g. OMNISTAB UV326, OMNISTAB UV1577, OMNISTAB UV531), synergistic effect will be obtained .
