Which resin, combined with a hardener, becomes hard and corrosion resistant, and is used for printed circuit boards and adhesives?

• A. Epoxy Resin
• B. Polyester Resin
• C. Phenol Formaldehyde
• D. Glass

Answer: (A)

Mixing a resin with a hardener triggers a chemical cure that links the molecules into a dense, crosslinked network. This makes the material hard, tough, and highly resistant to moisture and chemicals—perfect for protecting electronics and bonding surfaces. Epoxy resins are especially valued for printed circuit boards and adhesives because they cure into a strong, durable matrix with excellent dielectric properties and strong adhesion to copper and FR4 substrates. Other resins don’t offer the same combination of electrical insulation, moisture resistance, and strong bonding, so they’re less suitable for PCB encapsulation and many adhesive applications.