Applications of Novel Light Stabilizers for Environmentally Friendly Coatings

Author: Yang Yung –Jee / Tech. Engineer

 

Preface

High solids, powder, waterborne, and UV curable coatings - the green coatings - have been developed to replace conventional high VOC and solvent-based coatings.  It has overcome the disadvantages of traditional solvent-based coatings. However, the green coatings still need light stabilizers to help avoid degradation from sun light and improve weather stability.
Everlight Chemical Industrial Corporation (ECIC), a leading light stabilizer manufacturer, has developed several unique products specifically for green coatings.

Green Coatings and Light Stabilizers

Green coatings mean high-solids, powder, waterborne and UV curable coatings. It is designed to eliminate the release of VOC (Volatile Organic Compounds) from conventional solvent-based coatings. Every material contains chromophores or impurities. When UV light reaches chromophores,  coatings are easily degraded, discolored, lost of gloss, chalked and cracked.  Adding light stabilizers to coating is the most effective to solve these problems.

Light Stabilizers Recommended for Green Coatings

1. High-Solid Coatings:
Have been developed with solvent-based coatings. The objective is to reduce the requirement of organic solvents and increase solids content.
In choosing light stabilizers, it is necessary to consider its solubility at  coatings. Therefore, the liquid type light stabilizers are the first choice. Using Eversorb 80, Eversorb 81 and Eversorb 93 can reduce the damages caused by UV light---  discoloration, loss of gloss, etc.

2. Powder Coatings:
Powder coatings are applied by high pressure, static electrostatic
spraying to let resin and additives be attached to the surface of object
and then cured with heat to form a durable coating. This results a 
solvent-free coatings.
Particle size is critical in powder coatings. It is very difficult for light stabilizers to reach well homogenous disperse in a short time due to the small dosage. Eversorb 76H and Eversorb 60H, both are of novel micron grade, are developed for effectively overcoming the obstacle of dispersion.

3. Waterborne Coatings:
Water borne coatings are based on water soluble or water dispersed resins. It is non-toxic, odorless and nonflammable.
 Liquid light stabilizers are normally not easy to disperse in water-based coatings. Adding UV stabilizers directly to water-based paint system will cause condensation in coatings and make it difficult to spray. Eversorb AQ series are new high-performance liquid light stabilizers. They can be used directly and homogenously disperse in water borne coatings.
 
4. UV Curable Coatings:
 UV curable coatings require direct UV light to initiate monomers and oligomers. It is converted from a liquid into a solid film. Specialty about the UV curing coatings is its speed in production and faster in drying.
    Photoinitiators and light stabilizers usually conflict one another in UV curable system. Eversorb UR210 is a high-performance liquid-based light stabilizer and it does not affect curing speed.

Conclusion

 Environmentally friendly coatings are the trend for future development. Everlight Specialty Chemical Division has developed several unique products specifically for coatings. It will prevent degradation and increase the durability of coatings.

 

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