New Master Bond UL-certified epoxy is arc and flame-resistant

The new Master Bond EP21AC is a two-part epoxy with a non-halogenated filler that’s formulated for applications that require arc-resistance and flame-retardancy.

Electrical arcing is a challenge for several electronic or electrical devices. It occurs when electricity jumps from one connection to another, resulting in an electrical breakdown. The air surrounding the current becomes ionized and arcs, which can lead to combustion and fire.

The 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 PLC [performance level category] of 0 under the UL746A High Amp-Arc Ignition test,” said Rohit Ramnath, senior product engineer.

“The compound is also flame-retardant, as per the UL94HB standard for flammability testing,” he added. “This combination of unique performance properties makes EP21AC suitable for encapsulating, potting or coating in many demanding applications.”

The epoxy is toughened, with an elongation of 10 to 20%, and is capable of resisting thermo-mechanical stresses. It’s 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 5,000-6,000 psi, and a tensile modulus of 300,000-350,000 psi at 75° F. It is serviceable over the temperature range of -60° to +90° C (-75° to +194° F).

The new EP21AC cures at room temperature or more rapidly with heat. It has good flow properties with a mixed viscosity of 30,000-50,000 cps, 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, as well as several plastics and rubbers. It’s available for use in ounce kits, half-pint, pint, quart, and gallon container kits. Specialty packaging is also available in premixed and frozen syringes.