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

    Check access

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    Yellowing in Automotive Clearcoats


    Additional title:

    Sae Technical Papers


    Contributors:

    Conference:

    SAE 2016 World Congress and Exhibition ; 2016



    Publication date :

    2016-04-05




    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English




    Yellowing in Automotive Clearcoats

    Templeman, Cynthia | British Library Conference Proceedings | 2016


    Low VOC Automotive Clearcoats

    Gregorovich, Basil V. / Matheson, Robert R. | SAE Technical Papers | 1994


    Evaluation of Finesse/Polish of Automotive Clearcoats

    Jenkins, J. W. / Kane, K. M. / SAE | British Library Conference Proceedings | 1998


    Two pack polyurethane clearcoats for automotive finishing

    Kahl, L. / Bock, M. / Klinksiek, B. et al. | Tema Archive | 1995


    Automotive Clearcoats: Factors Affecting Service Life Prediction

    Wineburg, I. | British Library Conference Proceedings | 1995