Astronomy and space
Why Use Flame Resistant Adhesives and Potting Compounds?
October 18, 2018
Master Bond flame resistant epoxy and silicone compounds are formulated to increase escape time, prevent injuries, save lives and protect property from smoke, toxicity, flames in trains, planes, buses, electrical/electronic devices, appliances. Select Master Bond grades have been developed to meet customer application requirements and certified to satisfy governmental/national recognized fire safety standards. It is important to note that governmental flame resistant specifications differ from country to country. Utilization of these products has been successful in reducing safety hazards, minimizing the need for replacement parts and mitigating the risks posed by employing inappropriate adhesive systems. Catastrophic consequences that can result from flammability reinforce the emphasis placed by design engineers in selecting the most desirable compounds to avoid faulty devices/equipment.
Master Bond two component UL94V-0 epoxy systems are engineered for potting, encapsulation and casting. These user friendly compositions have a simple one to one mix ratio by weight, low viscosity, toughness, thermal shock resistance, outstanding dielectric properties. They contain non-halogenated fillers, feature low smoke emissions and are self extinguishing. Specimens measuring 120-130 mm in length, 12 mm-13.5 mm in width and 2.75-3.25 mm thick were vertically tested to satisfy stringent UL94V-0 specifications. Self extinguishing occurred within 10 seconds. Additionally to pass the vertical burn test cotton placed beneath the specimen will not ignite from the drips. These UL94V-0 potting polymeric resin formulas are globally recognized for use on switches, connectors, sensors to transformers, power supplies, PCB boards, control modules, capacitors, resistors. Free flowing antimony free systems fill small gaps, cavities, tight clearances to provide void free insulation to maximize effectiveness.
Flame Retardant Epoxies
Special flame retardant silicone compounds combine high flexibility and thermal stability. Single component products require no mixing, have relatively fast set-up times, are non-corrosive and adhere well to glass, metal, many plastic substrates. They exhibit high elongation, superior electrical insulation properties, pass UL flame classification for thicknesses of 0.75 mm (UL94V-1) and for 3 mm thickness (UL94V-0). In contrast Master Bond’s moderate viscosity addition curing silicone passes UL94V-0 testing for flame retardancy. This two component product does not require exposure to air for complete cross-linking and can cure in thicknesses well beyond 1-2 inches. Formulas are 100% solids, have exceptional resistance to impact, shock and have low exotherm on cure. This select composition has excellent thermal conductivity and outstanding heat dissipative characteristics. This system has proven ideal for potting/encapsulation. (They have been instrumental in preventing five risks, especially in miniaturized electronic devices with accelerated processing power.)
Durable fire resistant epoxy systems pass vertical and horizontal burn tests per FAR, 4CFR 25.853(a) for bonding, sealing, coating, potting applications. Products EP90FR-H, EP90FR-V, EP90FR-HFL were tested per Amendment 25-116 and Part 25 Appendix F. They were developed for use in aircraft interiors such as cabin, and cargo compartments. Importance of these tests are extremely critical because of the dangers emanating from flames, smoke emissions, toxicity levels in such confined areas. A sample is put into contact with a flame for a specified time frame and angle. Burn rates, burn lengths and time are carefully measured to ensure formulations meet these stringent specifications. These ROHS compliant products do not contain any substances of very high concern as per REACH.
Additionally Master Bond epoxy EP93FRHT meets vertical burn tests, smoke emission, toxic gas emission for demanding Airbus requirements. Standards are per ABD0031, Issue F, June 8, 2005 for floor and door assemblies, frame linings, internal panels. Post cure will optimize properties. Serviceability of this product is from -80°F to +400°F. EP93FRHT has outstanding elecgtrical insulative characteristics and can be used for potting. Master Bond EP90FR-V passes Boeing Standard B7238 Revision C for low smoke density and BSS7239 Revision A for low toxicity. It also meets FAR 25.853(a) vertical burn test/specification. It can be conveniently processed and has low shrinkage upon cure.