 | Clariant's comprehensive line of CESA additive masterbatches offers unprecedented opportunities to improve the properties, performance and quality of finished products, while also optimizing productivity and costs. |
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The CESA-light family includes three major classes of UV stabilizers: UV absorbers; Nickel quenchers; and Hindered amine light stabilizers (HALS).
UV Absorbers, which absorb harmful UV radiation, dissipating it as "harmless" thermal energy. Widely used in food, drug and personal care packaging, these active ingredients perform best in products with relatively thick wall sections, such as transparent blister packaging and hollow cosmetic tubes. Films, fibers and other products with thin cross sections will be afforded only limited protection by UV absorbers.
Nickel quenchers, which take over the absorbed energy and dispose of it either as heat, or as fluorescent or phosphorescent radiation. Their action is independent of polymer thickness, and they are mainly used to stabilize pesticide-resistant agricultural films. | | UV TRANSMITTANCE |
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LIGHT STABILIZATION | | | | |
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 | | Hindered amine light stabilizers (HALS), which do not absorb UV radiation, but act as radical interceptors, effectively inhibiting polymer degradation. Significant stabilization levels can be achieved at relatively low concentrations, regardless of wall thickness.
Although current understanding of HALS is incomplete, it is believed that they convert nitro-oxyl free-radicals under photo-0xidative conditions and may also cause the deactivation of carbonyl groups.
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| HALS and UV absorbers are frequently used in combination to achieve the highest possible levels of light protection. |
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