17.1 INTRODUCTION

Epoxy adhesives have achieved their commercial success due in no small way to their processing capabilities. Epoxy chemistry is compatible with (1) a variety of formulating techniques and processes accessible to the adhesive manufacturer and (2) a variety of application and curing methods accessible to the end user.

The role of the adhesive formulator has become so important that it has been associated with the creation of "new" or "engineered" adhesives. New products actually come both from the development of new polymeric materials such as resins and curing agents and from the creation of more versatile and usable adhesives through selecting, blending, filling, and modifying existing raw materials. With adhesive systems the easiest and most economical method of producing new products is arguably through formulating.

Epoxy resins are not ideal adhesives in their natural form; so they are mixed with materials to improve and enhance their properties and, thereby, make them more useful in a variety of applications. This process is called compounding or formulating. Compounding is the combining of a base epoxy resin with curing agents, modifiers, additives, reinforcement, tillers, and other polymers to make the base polymer perform better, cost less, and process more easily.

Under this broad definition there are two groups that perform compounding: (1) the suppliers of the base resins or adhesives and (2) the end users of the adhesive system.

Most often the compounding is done by the formulators who are specialists in compounding methods and equipment. They can marry...