UV Stabilizers

Abstract Ultraviolet stabilizers extend the service life of plastics and coatings by the inhibition of degradative processes photoinitiated by UV light from the sun and other UV sources. Several chemical classes of UV stabilizers have been developed over the years. Hydroxy benzophenones and hydroxyl benzotriazoles were the first commercial UV absorbers to be introduced and are still in use today. The next major stabilizer development was the introduction of hindered amine light stabilizers (HALS), which function by multiple mechanisms. More recently, specialty UV absorbers of the hydroyphenyl triazine class were introduced for more demanding applications or to satisfy specific market needs. Today synergistic combinations of absorbers, HALS, and other light stabilizers satisfy the UV stabilization requirements of most of the large volume outdoor polymer applications. The aforementioned light stabilizers together with other additives, such as antioxidants, impact modifiers, colorants, fillers, micronized inorganics, heat stabilizers, and plasticizers, have enhanced the properties and extended the service life of polymeric materials, resulting in the replacement of traditional materials in a multitude of outdoor weatherable applications. The effective use of light stabilizer products requires a basic understanding of polymer photodegradation processes, UV stabilization mechanisms, desired end‐use properties, and weathering testing program design. This article will provide a brief review of these various elements, together with some current application examples.