Why Composite Applications Often Stick with Epoxy Resin

Epoxies are widely used as structural adhesives because they are useful in a wide range of applications. Their versatility is attributed to their superior chemical resistance, performance under high temperatures, and strong adhesion strength and flexibility, among other benefits. Epoxy boasts high-performing mechanical, electrical and physical properties and meets the needs of industries including wind energy, aerospace marine, automotive, and infrastructure.

What makes epoxy so tough?
Epoxy is used to bind fiber-reinforced polymers (FRP), and is compatible with all common reinforcing fibers, including fiberglass, carbon fiber, aramid, and basalt. Epoxies consist of a base and a curing agent that are mixed in a certain ratio. Epoxy resins are cured with the addition of the curing agent, commonly called a hardener. Commonly used epoxy resin curing agents include amine, Bisphenol A and Bisphenol F. Epoxy resin can be made tougher with the addition of thermoplastic polymers.

How epoxies are used in composites manufacturing
Epoxy resins can be cured in a variety of environments, as well as without any other material added. This versatility in the production process makes them attractive for adhesive applications.

Fiber-reinforced epoxies can be used with a variety of composites manufacturing processes and may require differing temperatures and curing rates to be effective in their specific applications. Here are some of the composites manufacturing processes that use epoxy.
• Filament Winding: The process of winding fiber material and resin around a shape, or mandrel, to create a composite product.
• Pultrusion: A continuous and highly automated process that is cost-effective in high volume production runs of constant cross-section parts.
• Compression Molding: Heated steel tooling used in high-pressure presses to mold more complex, high-volume parts with fast cycle times.
• Prepreg: Reinforcement materials that have been pre-impregnated with a thermoplastic or thermoset resin.
• Autoclave: Pressure vessels used to process parts and advanced composites materials that require exposure to elevated pressure and temperature.
• Vacuum Infusion: A method of molding resins and fibers with extreme precision by using vacuum pressure to drive resin into a laminate.

The versatility of epoxies in these various manufacturing methods makes it viable by many industries and applications. Beyond this, epoxies offer advantages over thermoset or thermoplastic resins that may have been traditionally used in similar processes. Epoxy resins have exceptional mechanical and fatigue strength that enables them to perform with resistance to moisture, chemical, impact and under curing conditions.

Learn more about epoxy and curing agents available from Composites One.