Preface

In the first edition of this book, I tried to summarize the experiences, information, values, successes, and disillusions that I had experienced with adhesives or sealants during the first 30 years of my professional career. This was primarily as a user of these products in two large, multidivisional corporations: Westinghouse and ABB. As a result, the first edition looked at the vista from very much an end-user’s perspective.

Since that time, I have had the opportunity to work as an independent consultant with clients on applications that were not only more varied but that have highlighted the value of the formulator. I also have the good fortune to work as a technical advisor to Special Chem S.A. (www.specialchem4adhesives.com). This company addresses the informational needs of the formulator and raw material producers as well as the end-user. My work with SpecialChem, their client-partners, and the vast number of SpecialChem Internet users has led me to write this second edition.

So this edition is not only an updating of information, it also represents a somewhat broader perspective on the important subject of adhesives and sealants. I have tried to move a bit upstream and illuminate the challenges and opportunities available to both the formulator and the end-user.

At first glance, the job of the adhesive or sealant formulator appears deceptively simple. There are many resources on the supply side of the industry for the formulator to use. Sometimes it seems that almost all the polymers that have ever been made have been or could be used as adhesives or sealants. New resins and additives are generally developed for other industries, but they are available to the formulator as well. (One only has to wait and see how nanomaterials will eventually become ingrained into these products.) The industry is one that has been around since at least the ancient Egyptians—and yet, it was difficult to find a good practical text on adhesive and sealant formulations. I have tried to correct this with Epoxy Adhesives Formulations (McGraw-Hill, 2005) and with this second edition of Handbook of Adhesives and Sealants.

The problem is that, although there are a lot of tools at the disposal of the formulator, there seems to be an even more staggering amount of requests for new products on the demand side of the industry. These requests mount each day, as is evident from the number of questions asked and answered on the SpecialChem4Adhesives site.

The formulator has the unenviable task of responding to the latest issues impacting end-users and to devise the technology and resources to come up with practical solutions. It may seem that as soon as a product is developed, tested, and introduced commercially, the demands change. This is, of course, not necessarily the fault of the end-user. There are many outside influences that affect the end-users’ processes, just as there are many influences affecting the type of raw materials and equipment that can be utilized for formulating adhesives and sealants.

The formulator’s job has certainly not gotten any easier in the last few years. Substrates continue to undergo significant transformations. Today’s formulator is faced with the challenge of adhering to surfaces with a broad range of surface energies and to products that have only recently been developed and characterized. A competitive marketplace also necessitates the use of the most economical substrates available. These substrates may contain extenders and cost-reducing additives that are not compatible with the adhesives or sealant systems. Often cost-reducing changes are made without notice to the end-user or adhesive formulator.

In an age of increasing environmental concerns, many of the tools that formulators had utilized in the past are no longer acceptable. Use of solvents has drastically been curtailed. Plasticizers must often be used in limited amounts. Regional regulations place demands that total VOC emission be kept to a minimum. Certain catalysts and additives are discouraged because of safety or health issues.

Another megatrend in the competitive marketplace is that all production needs to be “world class” and “lean.” This means that processes must be automated; lead times shortened; rework, scrap, and waste must be minimized or eliminated; and less product must appear in inventory. This places a burden on the adhesive and sealant formulators in that their products must not only perform in service (e.g., creep resistance, peel strength, etc.), but they also must “perform” in the assembly process (e.g., fast cure time, minimal scrap, low energy cure, etc.)

New materials, pricing pressures, tougher environmental issues, continual customer requests to do it better, faster, and cheaper—these are the laments of adhesive and sealant formulators worldwide. Relying chiefly on innovation and brain power, today’s adhesive formulator is meeting the continual challenges that are part of this industry.

This edition, like the first, seeks to provide the knowledge needed to select and apply adhesives and sealants, but it also provides information on how the formulator “engineers” a product. This second edition is divided into five major sections. The first section, Chapters 1 through 11, describes the fundamental technologies. Here I have added chapters to describe the critical factors that contribute to success or failure in bonded joints, as well as the unique property requirements for these materials. I have also added a new chapter on test methods to achieve and verify consistency.

Chapters 12 through 17 introduce adhesive formulations and the types of base polymers that are most often used. Here new information is included regarding formulations and new materials. Chapter 16 (Naturally Occurring Adhesives) is also broadened to include and elaborate on older but still widely used adhesives. In Chapters 18 through 20, a similar process is used to describe sealant systems. In Chapters 21 through 24, I indicate the various processes by which these products cure or set. Many of the newer processes—such as induction curing, weld bonding, reactive hot melts, etc.—are important in today’s production environments.

Chapters 25 through 29 review the effect of the production environment and the endservice environment on adhesives and sealants. The environmental and safety considerations in using these products are significantly expanded from the first edition. The final chapter takes a more thorough look at major industries and how adhesives and sealants are affecting these industries and how the industry demands are affecting adhesives and sealants. Unique requirements, materials, and processes used in these important markets are discussed.

I take this opportunity to thank all those individuals and firms who have been kind enough to provide information and advice. The “life” behind this book is very much due to the end-users, formulators, and raw materials suppliers that work with adhesives and sealants. I hope they find that this is the most well-used book on their bookshelf.

EDWARD M. PETRIE