Yellowing in Automotive Clearcoats

Paper #:
  • 2016-01-0538

Published:
  • 2016-04-05
DOI:
  • 10.4271/2016-01-0538
Citation:
Templeman, C., "Yellowing in Automotive Clearcoats," SAE Technical Paper 2016-01-0538, 2016, doi:10.4271/2016-01-0538.
Pages:
5
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.
Access
Now
SAE MOBILUS Subscriber? You may already have access.
Buy
Select
Price
List
Download
$27.00
Mail
$27.00
Members save up to 40% off list price.
Share
HTML for Linking to Page
Page URL

Related Items

Standard
2001-12-11
Article
2016-02-02
Article
2016-02-02
Training / Education
2011-04-20
Standard
1992-10-01
Technical Paper / Journal Article
2003-01-18