Master Bond (Hackensack, NJ) says the new grade, marketed as EP42HT-2ND2MED (Black), is an excellent electrical insulator with a volume resistivity greater than 1012 ohm-cm, a thermal expansion coefficient of 35 - 40 in/in x 10-6/°C, a dielectric constant of 3.8, and a tensile strength exceeding 12,000 psi at ambient temperatures. Heat resistant up to 232°C (450°F) , it also withstands chemicals such as inorganic and organic acids, alkalis, organic solvents, and aromatic hydrocarbons.
This epoxy cures at ambient temperature in 48 - 72 hours. Its optimal curing schedule is overnight at room temperature followed by 2 to 3 hours of heat curing at 100°C - 125°C. EP42HT-2ND2MED (Black) has a noncritical mix ratio of 100:40 by weight or 100:50 by volume, and a paste consistency with minimal flow when applied. It offers a working life of 30 to 45 minutes for a mixed 100-gram batch at ambient temperatures, which can be increased by using shallow mixing vessels or mixing smaller batches. Parts A and B for EP42HT-2ND2MED (Black) are available for use in syringes, half pints, pints, quarts, gallons, and five gallon containers.
