Thermally Conductive, Flame Retardant Encapsulant Passes FAR 25.853(a) Test

Feb. 25, 2019

Master Bond EP93AOFR is a two part epoxy that may be used in encapsulation and potting applications, as well as in bonding, sealing and coating. According to Rohit Ramnath, Senior Product Engineer, "This flame retardant non-halogenated system is not only thermally conductive, 9-10 BTU•in/ft2•hr•°F [1.30-1.44 W/(m•K)], but it is also a reliable electrical insulator with a volume resistivity greater than 1014ohm-cm. EP93AOFR has an easy to use 1:1 mix ratio by weight and a good flow profile with a mixed viscosity of 30,000-150,000 cps.”

The Federal Aviation Regulations (FAR) Standard 14 CFR 25.853(a) test is typically used for determining material compatibility for various components inside aircrafts. This material has met and exceeded the requirements for the vertical ignition test where castings of the epoxy EP93AOFR were exposed to flames for 60 seconds. The results show that it took under 4 seconds to extinguish the flames, well under the allotted 15 seconds permitted by the test. The second part of this test measures how far the flame spreads. EP93AOFR exhibited a burn length of just 1.2 inches, well under the maximum allowed of 6 inches.

EP93AOFR bonds well to a variety of different substrates including metals, composites, glass, ceramic, FR4 and other plastics. It is serviceable from -80°F to +300°F [-62°C to +149°C] and offers good chemical resistance to water, fuels, oils, and many common solvents. This system is available for use in ounce, ½ pint, pint, quart and gallon kits. It can also be purchased in premixed and frozen syringes.

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