Coating

Modern electronics have become part of our daily lives and the sophisticated electronic circuitry at the heart of these devices and systems must be reliable. Conformal coatings act as a barrier between the electronics and the environment, protecting the areas they cover while strengthening delicate components and traces. Find out more about how conformal coatings enhance the reliability and longevity of electronic printed circuit boards.

Master Bond UV15-7HP is a low viscosity, easy to apply, one-part, UV curable adhesive system. Optimal adhesion is achieved in bond line thicknesses of 0.001-0.003 inch, and it can cure rapidly with a minimum intensity of 20-40 milliwatts/cm2 using a UV light source emitting at a wavelength of 320-365 nm. The material can also be cured in sections up to 0.125 inch thick under appropriate conditions, making it suitable for bonding, sealing, coating, and encapsulation. UV15-7HP has a strong performance profile, featuring a tensile strength of 6,000-7,000 psi and a tensile modulus of 250,000-300,000 psi at room temperature. This toughened system resists thermal cycling and offers significant elongation of 5-10%. It is an electrically insulative material with a volume resistivity greater than 1014 ohm-cm. Optically clear with a refractive index of 1.54 at 589 nm, it is not oxygen inhibited and contains no solvents or diluents. UV15-7HP bonds well to a wide variety of substrates including glass, ceramics, metals and many plastics, such as polycarbonates, acrylics and polyester films. This system is serviceable in a wide range of temperatures from -80°F to 300°F. It is available in various packaging options: 10cc and 30cc syringes, ½ pints, pints, quarts, gallons, and 5-gallon containers.

Master Bond UV22DC80-1 is a UV+heat (dual) curable epoxy that researchers used in a prototype concentrator photovoltaic (PV) system. The UV system was chosen for some critical performance properties, including high temperature resistance, excellent dimensional stability, and compliance with NASA outgassing requirements.

Master Bond EP4S-80 is a one component, silver filled epoxy for bonding, sealing and coating. This NASA low outgassing approved system cures at the low temperature of 80˚C and bonds well to a variety of substrates. Watch this video to see how this low viscosity compound can be dispensed through a syringe or brushed on to create a protective coating.

Master Bond has launched EP53TC, a two-component epoxy designed for bonding, sealing, coating, and small potting applications where efficient heat dissipation is crucial. The epoxy is formulated with a specialty filler with a particle size ranging from 5 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.

With the trend toward smaller and smaller electronic devices, unintentional EMI/RFI interference has become more of an issue. Shielding of these interferences is critical and coatings can be successfully applied as protection on the materials used. In this paper, the different sources of interference are explored, as well as how coatings can play a critical role in protecting these sensitive components and boards.