Ex 74 UV Epoxy Resin

Circuit boards have components of varying heights. UV light cannot reach some shadow areas. Winsir Ex 74 UV Epoxy Resin uses both UV and moisture curing. Areas exposed to UV cure in seconds. Shadow areas exposed to air moisture cure slowly over 24 to 48 hours. We tested this ex 74 UV epoxy resin with a power supply factory in Shenzhen. Their boards coated with our resin passed 1000 hours at 85°C and 85% humidity with no insulation degradation. This product meets IPC-CC-830B standards. It is used in consumer electronics, automotive electronics, and industrial controls.

Winsir Ex 74 UV Epoxy Resin uses a urethane acrylate base with a latent moisture curing agent and free radical photoinitiator. At 25°C, viscosity is 150 to 300 centipoise. It is suitable for spraying or selective coating. Solid content is 100% with no VOC and no halogens. Appearance is a pale yellow clear liquid. UV cure conditions require 1000 to 2000 mJ/cm² from mercury or 365 nm LED lamps. Moisture cure conditions are 24 to 48 hours at 50°C and 85% relative humidity. Cured hardness is Shore A 50 to 70. Elongation at break is above 50%.

Winsir Ex 74 UV Epoxy Resin delivers reliable dual curing. UV exposure for 3 to 5 seconds gives initial cure with a tack-free surface. Shadow areas cure completely in 24 to 48 hours with no residual uncured monomer. For electrical insulation, volume resistivity per ASTM D-257 is 1×10¹⁵ Ω·cm or higher. Dielectric strength per ASTM D-149 is 40 kV/mm or higher. For aging resistance, it passes 85°C/85% RH testing for 1000 hours with no insulation degradation. It also passes 200 thermal shock cycles from -40°C to +125°C with no cracking.