The epoxy is formulated with a specialty filler with a particle size ranging from five to 30 microns. It is a flowable system with a mixed viscosity of 45,000-65,000 cps at room temperature. This filler size and its relatively flowable viscosity enable the EP53TC epoxy to fill small voids, making it ideal for heat dissipation.
EP53TC meets ASTM E595 NASA low outgassing specifications and provides reliable electrical insulation with a volume resistivity greater than 1014 ohm-cm. The material offers a thermal resistance of 10-15 x 10-6 K•m2/W and a thermal conductivity of 2.3-2.6 W/(m•K). This epoxy exhibits dimensional stability with low shrinkage upon curing and a low coefficient of thermal expansion of 14-16 x 10-6 in/in/°C. Mechanical properties include a tensile strength of 5,000 to 7,000 psi, a tensile modulus greater than 1,000,000 psi, and a Shore D hardness of 85-95. The service temperature range is from -100ºF to +300ºF (-73ºC to +149ºC).
A moderate heat cure is required to achieve optimal properties with EP53TC. The recommended cure schedule is 2 hours at 80ºC followed by a post-cure of 90-120 minutes at 125ºC. This epoxy is available in various packaging options, including ounce kits, quarter pint kits, half pint kits, pint kits, and quart kits.
Last year, Master Bond offered EP42HT-2FG Black, a two-part, moderate heat cured epoxy with high temperature resistance that complies with FDA 21 CFR 175.105 for indirect food contact applications.
The epoxy is said to withstand exposure to a range of harsh chemicals, including acids, bases, and solvents. It possesses good flow properties and can be employed for bonding, sealing, potting, and casting.
This compound has a relatively long working life of 105-150 minutes for 100 grams of the mixed material at 75°F. The colour of Part A is black, and Part B is light amber, with a mix ratio of 100 to 30 by weight. EP42HT-2FG Black cures optically opaque, and the recommended cure schedule is overnight at room temperature, followed by a heat cure at 150-250°F for three to four hours.
