Sometimes you do everything right when painting something but then the sun comes along and ruins all your efforts. The coating fades, cracks appear, and the surface starts peeling. This is frustrating and you know that you need some additional protection for the paint.
That is where UV absorbers come to the rescue.
In this blog, we will tell you what they are, how they help, why you need them and how to choose the right one.
What Exactly Are UV Absorbers?
UV absorbers are chemical additives that absorb the energy of ultraviolet light before it affects the coating. They prevent the sun from degrading the polymer chains, pigments and other substances included in the composition. Benzotriazole derivatives, benzophenones, and hydroxyphenyl triazines are the most common classes of UV absorbers.
Why Does the Sun Damage Coatings?
Sunlight contains UV energy, which breaks chemical bonds between the atoms of the polymers in the coatings. Thus, it causes their degradation, resulting in cracking and fading of the surface. Cars exposed to the sun all the time and any kind of factory equipment have to face this issue. Without proper protection, even top-notch coatings lose their properties in just a few years.
How UV Absorbers Protect Coatings from the Sun?
It may seem surprising but UV absorbers absorb the energy of photons, turn it into thermal energy and return to the initial state again and again. This process continues until the additive loses its effectiveness. In addition, many formulators combine UV absorbers and hindered amine light stabilisers (HALS) in order to provide even more protection.
In this combination, the UV absorber is responsible for blocking the incoming UV rays, while HALS remove free radicals formed during this process.
Benefits of UV Absorbers in Industrial and Automotive Coatings
Thanks to UV absorbers, you can increase the service life of the coatings, improve their glossiness and colour stability. In addition, you can also increase resistance to weather changes, humidity, and temperature variations, and save on maintenance costs. Automotive clear coatings remain bright for many years instead of fading after one summer, and industrial coatings for tanks, bridges and other outdoor equipment resist sun exposure as well. Actually, the same principle of action is used in the UV absorber for personal care products. It helps protect creams, sunscreens and other skin care products from degrading in the sunlight. The principle of action is the same, but the molecules of the additives are different. A cosmetic UV filter and an industrial UV absorber for coatings cannot be interchangeable despite the similarity in functionality.
How to Choose the Right UV Absorber?
The selection of the optimal UV absorber depends on the type of the coating and the application technique. There are UV absorbers that work better with solvent-based, water-based or powder coatings.
You should also consider how the absorber interacts with other additives like HALS or antioxidants. Accelerated weathering testing like QUV or xenon-arc exposure is very helpful to prove the efficiency of the additive.
Regulatory Requirements for UV Absorbers
The list of regulations for the usage of chemical additives is rather frequently updated and varies from country to country. Therefore, you should always keep yourself informed about the recent updates of the regulations issued by organisations like REACH, TSCA and others before the finalisation of the formulation. Do not rely on old data and contact the chemical suppliers to clarify the situation.
Conclusion
Nowadays, UV absorbers are not an option but a must for any coating. No matter whether you work with automotive finishes or heavy industrial equipment coatings, UV absorbers will help you significantly extend their lifespan.
If you are looking for highly efficient UV absorbers and other speciality chemicals, we recommend you visit Sarex. Sarex is the online marketplace for highly efficient and innovative fine chemicals and textile chemicals in India.
The company has vast experience in the bulk manufacturing and exporting of its products. Contact Sarex now to make your coating more resistant to the sun.