This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Yellowing in Automotive Clearcoats
Technical Paper
2016-01-0538
ISSN: 0148-7191, e-ISSN: 2688-3627
Annotation ability available
Sector:
Language:
English
Abstract
Automotive clearcoats have many purposes, from providing a glossy finish to protecting the underlying paint layers from UV radiation. Yellowing of clearcoats is a natural phenomenon during weathering processes, as well as from extreme baking conditions, due to polymer degradation. However, occasionally yellowing may be caused by unexpected chemical reactions occurring in the clearcoat. These reactions may happen very quickly (within hours or days) or take years to manifest, as other chemicals migrate into the clearcoat. We have investigated one family of these unexpected reactions which occur with certain UV absorbers, as well as how to prevent the reactions from occurring. We found that certain benzotriazole UV absorbers react readily with some common metals, including copper and zinc, provided that the UV absorber is not in its excited state. The conformational change that occurs within the benzotriazole when it absorbs UV radiation effectively inhibits the reaction with metals.
Recommended Content
Ground Vehicle Standard | Split Type Bushings – Design and Application |
Technical Paper | New Chemical Surface Treatments for Processing Titanium |
Technical Paper | Response of Aluminum Alloys to Temperature Exposures Observed in Automotive Service |
Citation
Templeman, C., "Yellowing in Automotive Clearcoats," SAE Technical Paper 2016-01-0538, 2016, https://doi.org/10.4271/2016-01-0538.Also In
References
- Valet , Andreas Light Stabilizers for Paint Hannover Vincentz 1997
- Goldschmidt , Artur , and Streitberger , Hans-Joachim BASF Handbook on Basics of Coatings Technology Hannover Vincentz 2003
- Abdullayev , E. , Price , R. , Shchukin , D. , Lvov , Y. Halloysite Tubes as Nanocontainers for Anticorrosion Coating with Benzotriazole Applied Materials and Interfaces 1 7 1437 1443 2009 10.1021/am9002028
- Chen , X. and Häkkinen , H. Divide and Protect: Passivating Cu(111) by Cu-(benzotriazole) 2 Journal of Physical Chemistry C 116 22346 22349 2012