Failure Analysis of Paints and Coatings. Revised Edition

Size: px

Start display at page:

Download "Failure Analysis of Paints and Coatings. Revised Edition"

Oswin Atkins
6 years ago
Views:

1 Failure Analysis of Paints and Coatings Revised Edition Dwight G. Weldon Weldon Laboratories, Inc, Imperial, PA, USA A John Wiley & Sons, Ltd., Publication

3 Failure Analysis of Paints and Coatings Revised Edition

5 Failure Analysis of Paints and Coatings Revised Edition Dwight G. Weldon Weldon Laboratories, Inc, Imperial, PA, USA A John Wiley & Sons, Ltd., Publication

6 This edition first published John Wiley and Sons, Ltd Registered offi ce John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, United Kingdom For details of our global editorial offices, for customer services and for information about how to apply for permission to reuse the copyright material in this book please see our website at www. wiley.com. The right of the author to be identified as the author of this work has been asserted in accordance with the Copyright, Designs and Patents Act 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, except as permitted by the UK Copyright, Designs and Patents Act 1988, without the prior permission of the publisher. Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic books. Designations used by companies to distinguish their products are often claimed as trademarks. All brand names and product names used in this book are trade names, service marks, trademarks or registered trademarks of their respective owners. The publisher is not associated with any product or vendor mentioned in this book. This publication is designed to provide accurate and authoritative information in regard to the subject matter covered. It is sold on the understanding that the publisher is not engaged in rendering professional services. If professional advice or other expert assistance is required, the services of a competent professional should be sought. The publisher and the author make no representations or warranties with respect to the accuracy or completeness of the contents of this work and specifically disclaim all warranties, including without limitation any implied warranties of fitness for a particular purpose. This work is sold with the understanding that the publisher is not engaged in rendering professional services. The advice and strategies contained herein may not be suitable for every situation. In view of ongoing research, equipment modifications, changes in governmental regulations, and the constant flow of information relating to the use of experimental reagents, equipment, and devices, the reader is urged to review and evaluate the information provided in the package insert or instructions for each chemical, piece of equipment, reagent, or device for, among other things, any changes in the instructions or indication of usage and for added warnings and precautions. The fact that an organization or Website is referred to in this work as a citation and/or a potential source of further information does not mean that the author or the publisher endorses the information the organization or Website may provide or recommendations it may make. Further, readers should be aware that Internet Websites listed in this work may have changed or disappeared between when this work was written and when it is read. No warranty may be created or extended by any promotional statements for this work. Neither the publisher nor the author shall be liable for any damages arising herefrom. Library of Congress Cataloging-in-Publication Data Weldon, Dwight G. Failure analysis of paints and coatings / Dwight G. Weldon. Rev. ed. p. cm. Includes bibliographical references and index. ISBN (pbk.) 1. Paint Testing. 2. Coatings Testing. I. Title. TP936.5.W dc A catalogue record for this book is available from the British Library. ISBN: (Cloth) Set in 10 on 12 pt Times by SNP Best-set Typesetter Ltd., Hong Kong Printed and bound in Great Britain by TJ International, Padstow, Cornwall

7 To my son Andy, who can still make me smile.

9 Contents Preface to the Revised Edition Preface to the First Edition Acknowledgements xiii xv xvii 1 General Principles of Coating Formulation Introduction Binders Pigments Solvents Additives Formulation Concepts: Pigment-to-Binder Ratio Formulation Concepts: Pigment-Volume Concentration Formulation Concepts: Density, Weight Solids and Volume Solids 7 References 8 2 Why Coatings Work and Why They Fail Why Coatings Work Adhesion Wetting Surface Preparation Cohesive Strength Permeability Why Coatings Fail Mechanical Stress Internal Stress Chemical Attack Weathering Stress 33

10 viii CONTENTS Osmotic Blistering Electroendosmotic Blistering 35 References 36 3 Pigments Inorganic Pigments Inorganic Colour Pigments White Inorganic Colour Pigments Yellow Inorganic Colour Pigments Orange Inorganic Colour Pigments Red Inorganic Colour Pigments Blue Inorganic Colour Pigments Green Extender Pigments l Silica/Silicates Calcium Carbonate Barytes Corrosion-Resistant Pigments Organic Pigments Organic Red Pigments Organic Yellow Pigments Organic Blue Pigments Organic Green Pigments 50 References 50 4 Additives and Solvents Additives Anti-settling Agents Viscosity Modifiers Surfactants and Emulsifying Agents De-foaming and Anti-foaming Agents Driers Plasticizers Ultraviolet Stabilizers Anti-skinning Agents Biocides Flow-Modifying Agents Solvents 57 References 64 5 Coating Types and Common Failure Modes Natural Resins and Oils Natural Resins Oils 68

11 CONTENTS ix 5.2 Alkyds and Epoxy Esters Alkyds Epoxy Esters Epoxies Amine and Amide Curing Agents for Epoxy Resins Epoxy Failure Modes Modified Epoxies Acrylic Epoxies Coal Tar Epoxies Epoxy Phenolics Phenolics Resole Phenolics Novolac Phenolics Phenolic Failure Modes Amino Resins Acrylics Solution Acrylics Acrylic Latex Coatings Thermoset Acrylics Polyesters Saturated Polyesters Unsaturated Polyesters Polyurethanes Two-Component Polyisocyanate/Polyol Coatings Urealkyds Moisture-Cured Polyurethanes Polyurethane Lacquers and Dispersions Two-Component Water-Borne Polyurethanes Vinyls Solution Vinyls Plastisols and Organosols Vinyl Fluorides Poly(vinyl butyral) Vinyl Latexes Bituminous Coatings Inorganic and Silicone-Modified Coatings Silicone Coatings Silicate Coatings Polysiloxane Coatings Polyureas Polyaspartic Polyurea Coatings Powder Coatings 122 References 124

12 x CONTENTS 6 Application-Related Problems Brush and Roller Spray Applications Air (Conventional) Spray Airless Spray Plural Spray Electrostatic Spray Flow Coating Roll Coating Powder Coating Coating Failures Related to Application Problems 129 References Field Methods Analytical Methods Light Microscopy Infrared Spectroscopy Theory Instrumentation Sample Handling Applications Gas Chromatography (GC) Theory of GC Instrumentation Pyrolysis-GC Application of GC Gel Permeation Chromatography (GPC) Theory Instrumentation Applications Ion Chromatography Theory Applications Scanning Electron Microscopy Imaging Theory Elemental Analysis by X-ray Spectroscopy Sample Preparation Applications of SEM-EDS Differential Scanning Calorimetry (DSC) Theory Calibration and Sample Preparation Applications of DSC Miscellaneous Methods of Analysis 258 References 259

13 CONTENTS xi 9 Physical Methods Adhesion Flexibility and Impact Resistance Solvent Resistance Weathering Resistance Chemical Resistance Freeze Thaw Application Variables 269 References Examples of Coating Failures Urethane Topcoat Disbonding from Epoxy Blistering of an Epoxy Tank Coating Cracking and Delamination of Epoxy Coating Systems on Masonry Walls Discolouration of Coil-Coated Aluminium Siding Discolouration and Delamination of Plastisol Delamination of Floor Coating Delamination of Dry-Fall Alkyd Coal Tar Epoxy Failure Splitting of Inorganic Zinc-Rich Primer Defects on Electro-Coated Panels Failure of Coated Light Poles Blistering of Coating on Concrete Floor, Number Blistering of Coating on Concrete Floor, Number Peeling of Paint from Metal Chairs Failure of Railroad Car Liner Failure of Calcium Sulfonate Modified Alkyd Topcoat from a Bridge Discolouration of Furniture Lacquer Failure of Tank Car Lining 337 References The Repair of Coating Failures 347 Index 351

15 Preface to the Revised Edition It has been over 8 years since the first edition of Failure Analysis of Paints and Coatings was published. During this period, many coating types have remained the same, and a few new ones have been introduced, or at least have been more heavily marketed. Advances have been made in surface preparation technology, and more opportunities for training and education have been made available than ever before. However, in spite of all of this, the coatings industry still experiences its fair share of failures. A coating failure does not just involve the cost of some paint. Repair of an existing structure can be extremely expensive, perhaps even entailing lost production time if the facility has to be shut down for repairs. If a coating lining a process vessel or a railroad tank car fails, large amounts of product may become unmarketable and may have to be disposed of. Reputations can be damaged. The cost of a paint failure is seldom cheap. The first edition of this book introduced some basic concepts in paint formulation and chemistry. This has been updated in the second edition to include some additional types of coatings, such as polyureas, polysiloxanes and powder coatings. Some additional discussion has been included concerning surface preparation, the mechanism of blistering and the chemistry of amine blush. Analytical techniques such as gas chromatography mass spectroscopy and differential scanning calorimetry have been discussed in more detail. However, as with the first edition, the subjects of coatings chemistry and analytical chemistry are presented at the introductory level. Although essential to conducting a failure analysis, many thorough texts already exist on these subjects. As pointed out in the preface to the first edition, the failure analysis of paints and coatings is all about problem solving. Problem solving is a difficult subject to teach, and probably relies on curiosity and experience more than anything else. Therefore, in addition to the basics of coatings science and analytical chemistry, which form the foundation upon which curiosity and experience can build, this book contains numerous practical examples of solving real - world coating failures. Indeed, the biggest difference between the first and second editions is

Pulse-Width Modulated DC-DC Power Converters Second Edition

Pulse-Width Modulated DC-DC Power Converters Second Edition Marian K. Kazimierczuk Pulse-Width Modulated DC DC Power Converters Pulse-Width Modulated DC DC Power Converters Second Edition MARIAN K. KAZIMIERCZUK