What is commonly called “epoxy” is more technically, “polyepoxide.” At its most basic level, the epoxy polymer starts with a resin resulting from the reaction of a base chemical compound (typically bisphenol-A, or bisphenol-F) with epichlorohydrin. To this is added a hardener to cause the crosslinking or, polymerization.
The chemistry of epoxies and the range of commercially available variations allows cured polymers to be produced with a very broad range of properties. In general, epoxies are known for their excellent adhesion, chemical and heat resistance, good to excellent mechanical properties and electrical insulating properties.
There are literally hundreds of variations on their basic chemistry. There are variations in the base resin selection. There are variations in the curing agent selection. Additionally, many modifications include the addition of fillers to add strength and toughness, viscosity reducers to thin the resins for penetration of substrates, thickeners to increase viscosity to use as putties, and even accelerators for quick curing times.
All of these modifications are made to either reduce costs, improve performance, or improve processing convenience. As a result, a typical formulator might offer a dozen different formulations, each specifically designed for a particular set of requirements.
Here in our structural adhesives department, to save you time and research, we have evaluated and selected the more popular and proven epoxy systems used and recommended for specific applications.
For a further understanding of the nature of epoxy chemistry, see our white paper in this section titled “Basic Epoxy Adhesive Chemistry.”