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Effect
Organic substrates tend to degrade during service life due to various mechanisms. Along with thermal, thermo-oxidative (induced by oxygen and heat) and hydrolysis initiated degradation (discussed above), UV light can initiate oxidation. Organic substrates which are used outdoors or exposed to lamps emitting UV radiation are subject to photo-oxidative degradation. An overview over photo- oxidation is provided in. UV-stabilizers are one of several tools to prevent and retard pho to- oxidation. Photo-oxidative degradation is a non- homogeneous effect that always starts at the surface (at the side exposed to UV light ) and propagate s throughout the sample. Using antioxidants can lead to an improved resistance against photo-oxidation. It must be further noted that a suitable stabilization during processing or conversion is mandatory for optimum stability against pho to- oxidation.
Influencing the stability against photo-oxidation, Apart from increasing the UV stabilizer concentration up to the saturation limit, stability against pho to-oxidative degradation can be increase d by:
+ thicker sample (film)
+ best possible protection during processing or conversion
+ surface coating with a protective layer.
Benefit:
- excellent UV-A and UV-B blocking
- long-term protection of goods and substrates
- no migration
- chemically inert
- low influence on clarity
- suitable for clear polymers and pigmented systems
- fine and uniform distribution of ZnO nanoparticles
- free-flowing, micro bead allows easy incorporation
- safe to use due to the embedded nanoparticles
- compliant with FDA and EU food contact regulations
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