Light Stabilizers Make the
UV Protection of Environmental
Friendly Coatings Easier
by By Yung-Chi Yang, Steven Lee
and Dr. Yao-Hsing Huang,
Everlight Chemical Industrial Corporation
High solids, powder, waterborne and UV curable coat- ings—the “green” coatings—have been developed to re- place conventional high VOC and solvent-based coatings.
Although the latest technology has overcome the disadvantages of
traditional solvent-based coatings, light stabilizers in green coatings still play an important role helping to avoid degradation from
sun light exposure and improve weathering stability. Everlight has
developed several products specifically for green coatings.
Green coatings and light stabilizers
Green coatings can be as diversified as high-solids, powder, waterborne and UV curable coatings and so on. They are designed
to eliminate the release of VOCs from conventional solvent-based coatings.
The cause of coating degradation such as discoloration, delamination, loss of gloss, cracking and chalking is due to the
chromophores, or impurity content, found in the material triggered by UV light, which is damaging. Therefore, UV absorbers
and light stabilizers are both recommended in order to prevent
coating decomposition.
Light stabilizers can be divided into two groups: UV absorbers (UVA) and the hinder amine light stabilizers (HALS).
UVA’s function is to absorb UV light and transform it into heat;
HALS is best known to capture free radicals and prevent material degradation.
Light stabilizers recommended for green
coatings
1. High-Solids Coatings
The objective with high-solids coatings is to reduce the requirement of organic solvents and increase solids content. Most coating systems need to use acidic catalysts to improve film hardness
during thermo-curing processes.
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