Epoxy/urethane coating systems are widely used for weather parts of ships and offshore structures due to its excellent resistance to UV radiation as well as corrosion protection. Recently, epoxy/epoxy coating systems or epoxy/urethane coating systems have experienced lots of premature coating failure such as intercoat adhesion failure during winter and spring seasons in Korea. In this work, the root causes of premature coating failure were investigated using pH test and Fourier transform infrared spectroscopy (FT-IR) for several failed epoxy/urethane coating systems. We found that coating failure was attributed to the amine blush and urea formation by the reaction of isocyanate(-NCO) with moisture and free amine. The premature coating failure have been successfully controlled by the use of amine adduct or amide adduct hardener and the proper control of atmosphere for coating application in the winter and spring seasons.

Subject
Films, Coatings, Isocyanates, Ammonium, Acidity, Epoxy coatings, Amines, Amide, Coating defects, Epoxies, Delamination, Urethane, Coating systems
Keywords:
Intercoat adhesion failure, amine blush, FT-IR, epoxy, urethane coating system
© 2009 Association for Materials Protection and Performance (AMPP). All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise) without the prior written permission of AMPP. Positions and opinions advanced in this work are those of the author(s) and not necessarily those of AMPP. Responsibility for the content of the work lies solely with the author(s).
2009
Association for Materials Protection and Performance (AMPP)
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