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  1. Master Bond
11 August 2022

UL Certified Epoxy Encapsulant Resists Arcing Without Igniting

Master Bond EP21AC is a two part epoxy with a non-halogenated filler that is formulated for applications where arc resistance and flame retardancy are required. Electrical arcing is a challenge for numerous electronic or electrical devices; this occurs when electricity jumps from one connection to another, resulting in an electrical breakdown. The air surrounding the current becomes ionised and arcs, which may lead to combustion and fire. EP21AC is designed primarily with the aim to prevent arcing related issues.

“EP21AC withstood over 150 arcs without igniting and therefore was assigned the highest performance level category (PLC) of 0 under the UL746A High Amp Arc Ignition test,” says senior product engineer Rohit Ramnath. “The compound is also flame retardant, as per the UL94HB standard for flammability testing. This combination of unique performance properties makes EP21AC suitable for encapsulating, potting, or coating in many demanding applications.”

The system is toughened, with an elongation of 10 to 20%, and is capable of resisting thermo-mechanical stresses. It is an excellent electrical insulator, with a volume resistivity greater than 1014 ohm-cm, and a dielectric constant of 4.7 at 75°F. Other noteworthy properties include a tensile strength of 5,000-6,000psi, and a tensile modulus of 300,000-350,000psi at 75°F. It is serviceable over the temperature range of -60°C to +90°C [-75°F to +194°F].

EP21AC has a convenient to use one to one mix ratio by weight and cures at room temperature, or more rapidly with heat. It has good flow properties, with a mixed viscosity of 30,000-50,000cps, and a relatively long working life of 75-120 minutes at room temperature. This compound bonds well to a variety of substrates including metals, ceramics, composites, and many plastics and rubbers. It is available for use in ounce kits, ½ pint, pint, quart, and gallon container kits. Speciality packaging is also available in premixed and frozen syringes.

For more information, please contact Masterbond via the contact details on our profile.

Structural polymers offer distinct advantages over traditional fastening methods.
Because of its outstanding strength and other physical properties, Master Bond Supreme 10HT has been selected for use in several published research studies.
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