Electrically insulative epoxy delivers low exotherm for large castings and potting applications

Master Bond EP39MAOHT is a room temperature curing system for demanding bonding, sealing, coating, potting and encapsulation applications. “It is a versatile product that combines convenient handing, good flow, thermal conductivity, electrical insulation and high temperature resistance,” said Robert Michaels, vice president of technical support. “Its toughness lessens the chance of stress cracking when thermally cycled and its low exotherm makes it particularly useful for mid-to-large sized potting applications.” The epoxy has a low mixed viscosity of 3,000-6,000cps as well as a convenient one to one mix ratio by weight and a long working life of 120-150 minutes for a 100g batch. This dimensionally stable system bonds well to a wide variety of substrates including metals, ceramics, composites and glass as well as many rubbers and plastics with very low shrinkage upon curing. This formulation features reliable thermal conductivity of 9-10BTU•in/ft2•hr•F [1.30-1.44 W/(m•K)], while retaining superior electrical insulation properties, including a volume resistivity of >1014ohm-cm and a dielectric constant of 4.8 at 60Hz. It offers chemical resistance to water, fuels and hydraulic fluids as well as many acids and bases. EP39MAOHT is serviceable from -100F to +400F. The combination of these performance properties makes it well suited for application in the aerospace, electronic, electrical, optical and specialty OEM industries. The epoxy is off-white in colour and is available for use in 1/2 pint, pint, quart, gallon and five gallon container kits.