Several coating systems and designs were chosen to protect a concrete chamber with side walls coated with a polyvinylidene fluoride (PVDF) material. When polyurea was identified as the coating to be used at this engineering pilot plant, which contains harsh caustic chemicals in conjunction with PVDF coated panel walls; an extensive research was conducted to determine which method will be utilized to create a seamless protective film between these two systems. In this area, there is a gap which exists between the floor and the vertical wall which varies between 1” and ¼”. To bridge the gap between the two surfaces, it was decided by the Engineer that galvanized flashing plates will be the metal of choice as most coatings are unable to have great adhesion to PVDF. This metal is easy to work with, readily available and from a cost perspective it will save the project over ninety percent of material costs compared to standard carbon steel plates. The selected coating system needs to be chemically resistant to all caustic chemicals in the plant as well as have an adhesion value greater than 400 psi.

This thirty gauge metal flashing will be prepped, coated and installed to keep any chemicals from reaching the gap thereby contaminating the concrete substrate. Four systems were used and tested on the galvanized flashing to determine which coating system will have the best adhesion to the marginally prepared galvanized flashing plates.

Although many coating systems were considered for this application, only four different coating systems were proposed to coat over the galvanized sheet metal designed to bridge the gap between the vertical PVDF coated wall and the horizontal concrete floor. The coating systems included the following: Polyurea over galvanized flashing, polyurea over scarified galvanized flashing, polyurea with a vinyl wash primer over scarified galvanized flashing and a polyurea with an acrylic primer over scarified galvanized flashing. This paper will discuss which coatings system exhibited the best adhesion value per ASTM D4541 “Pull –Off Strength of Coatings Using Portable Adhesion Testers”.

Subject
Primers, Protective coatings, Vinyls, Inspectors, Solvents, Galvanized coatings, Polyurea, Mechanical failure, Metals, Dry film thickness, Concrete coatings, Coating systems, Acrylics
© 2012 Association for Materials Protection and Performance (AMPP). All rights reserved. This work is protected by both domestic and international copyright laws. 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).
2012
Association for Materials Protection and Performance (AMPP)
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