Electrically Insulative Adhesives, Sealants, Coatings, Potting and Encapsulation Compounds - Features and Applications by Master Bond

Epoxies are the most widely used polymeric materials for adhesives, sealants, coatings, pottings and encapsulations and impregnants. They are available in both one and two component systems. Two part systems can be cured at either room temperature or elevated temperature. One part systems must be cured at elevated temperatures (typically 250 - 300°F). One part systems curable by UV light are also available.

Epoxies offer unique versatility in application and performance. Their most desirable properties include high bond strength to a wide variety of different substrates, outstanding gap filling capabilities, excellent electrical insulation, high chemical inertness and outstanding resistance to shock and vibration. Special formulations are available including systems with thermal conductivity (electrically insulating) for heat dissipation, electrically conductive systems, systems for cryogenic applications, as well as systems with high performance in the most hostile environmental conditions. Viscosities and cure times can be tailored to meet specific application requirements.

Silicones are elastomeric systems with the unique combination of flexibility and high temperature resistance. They can be used as adhesives, sealants, coatings and potting materials. Silicone systems are either one or two part. One part systems cure by moisture in the air. Two part systems are cured by the polymerization reaction that occurs when a curing agent is added. Generally, the two part systems can cure in thicker sections than the one part systems.

Aside from temperature resistance and inherent high flexibility, other noteworthy properties of silicones include excellent resistance to water, superb electrical insulation properties and sealing/adhesive properties particularly to glass, plastics, metals and rubber (including silicone rubber itself). Their inherent flexibility allows for “repairability” when this property is needed.

• For high performance potting, sealing, coating and bonding assemblies
• High frequency, high voltage applications
• For use with electrical components in high vacuum environments
• Encapsulation of sensitive electronic and electrical assemblies requiring heat dissipation and thermal shock properties
• For protection of components in motor armatures
• For use in miniature transformers and wound capacitors
• For applications requiring excellent resistance to mechanical shock
• Insulation of coils and transformers
• Coating of bus bars and torroid cores
• For applications where a low coefficient of thermal expansion is necessary
• For staking transistors, diodes, resistors, and heat sensitive components to printed circuit boards
• Heat sink bonding and solderless connections
• For use in joining SMDs to single or double sided PCBs
• For electrical component insulation in motors under high voltage
• Insulation of magnet wire
• For coating of stators in electric motors
• Optical sensors and wave guides
• Alpha particle protection of memory die

• For assembly of sensitive hybrid microelectronics
• Optical/fiber optical devices
• Potting of connecters
• Glob top protections over SMDs
• Potting IC packages like BGAs or CSPs
• Bonding of ferrites for power-devices
• Perimeter/main seal for LCDs
• Fiber optic pigtailing
• Micro molding lenses for LCD projection
• COB glob top “dam” encapsulation process
• Spin coating in semiconductor applications
• Glass-glass adhesive for CCD/CMOS semiconductor devices
• Adhesion to flex circuits
• For use in manufacturing of hard disk drives
• Optoelectronic instrumentation and assemblies
• Impregnation/insulation of copper coil windings
• Laminating PZT ferroelectrics
• Die attach adhesive