Why does epoxy yellow over time?
All resins will discolor over time. Epoxy, polyurethane, acrylic, etc.…they will all break down eventually with UV exposure.The epoxy resin itself (Part A) is an aromatic chemical structure, which in simple terms means the chemical bonds are susceptible to UV. UV stabilizers can be added to slow down the discoloration which increases the life of the epoxy. Discoloration is not only an aesthetic issue; it affects the transmission of light through the epoxy.
EB-107LP-2 is a low viscosity, long pot life epoxy system. A USP Class VI certified product, EB-107LP-2 is preferred by many medical device manufacturers for its extremely long work life and biocompatibility. Applications include matching layers in acoustic technology and underfill epoxy for PCB applications. Due to its unique chemical formulation, EB-107LP-2 resists yellowing for much longer than the life of LEDs making it a non-yellowing epoxy.
|Mix Ratio by Weight||100/35|
|Mixed Viscosity @RT(cps)||200-500|
|Pot Life @25°C(100 gram)||>8 hrs|
|Recommended Cure||3 hrs @ 65°C|
|Alternate Cure||24-48 hrs @ 25°C|
|Lap Shear Strength @25°C(psi)||2300|
|Service Temp.Range||-55°C to 200°C|
|Volume Resistivity(500 V)||>10^14|