No matter what the specific application or industry, protecting electronic components is crucial for ensuring long-lasting system durability and functionality. Available in various formats including encapsulates and gels, electronic potting compounds provide reliable protection for both complex and simple components in any type of environment.
Silicone encapsulates, in particular, contain no solvents or cure byproducts, allowing for lower costs. Providing optical clarity and thermal conductivity, they can perform in temperatures ranging from -45°C to 200°C. Silicone gels, on the other hand, provide ideal protection from moisture, as well as thermal and mechanical stress. They also protect against bubble or crack generation in high-voltage applications.
Some of the industry's top manufacturers offer several types of electronic potting compound materials to help minimize stress and maximize reliability for flexible and rigid print circuit boards (PCBs), LED lighting and displays, industrial equipment, high-voltage electrical components, and power modules, among many other devices and systems. Robert McKeown carries a wide range of Dow and Henkel Adhesive products; just a few of their many offerings are outlined below.
Dow Silicone Encapsulants
Used to protect circuitry from mechanical or thermal shock, vibration, chemical attack, humidity, and other stressors, Sylgard® silicone encapsulates from Dow provide unmatched electronics encapsulation.
Silicone encapsulates are available in two main types: condensation cure and addition cure, both of which can be supplied as one-part or two-part electronic potting compound systems to meet specific application needs.
One-part condensation cure silicones allow for ease of application and easy dispensing from a cartridge or tube, making these encapsulates ideal for thin-section cures of less than 7 millimeters. However, fixed cure speeds are required, and viscosity options are limited. Two-part condensation cure silicones, on the other hand, have a high tolerance to variations in the catalyst ratio and limited risk of inhibition. They do have slightly higher shrinkage levels than addition cures, however, as well as a reversion to liquid if heated in a container.
As with one-part condensation cure systems, one-part addition systems also allow for optimal ease of application. Featuring good physical strength, they can be used for both thin and thick section cures. However, they require heat to cure and have a short shelf life. Two-part addition cure systems allow for excellent deep section cures and low shrinkage rates. Their pot life can also be easily extended with an additive. Adequate adhesion is difficult to achieve with these two-part electronic potting compound systems, however, and they’re also prone to inhibition.
Henkel Loctite Epoxy Catalysts
Another ideal option for electronic potting applications, Loctite® epoxy catalysts from Henkel Adhesives offer excellent adhesion, high chemical resistance, and high-temperature physical properties. Epoxies are also extremely rigid and have a high tensile strength. And because most epoxies provide electrical insulation and have great moisture resistance, they’re ideal for outdoor use.
Two-Part Epoxy Compounds
Mix ratios are used for two-component epoxy systems to determine the amount of resin and epoxy catalyst needed for a full cure. The chemical makeup of the resin and the catalyst determine the mix ratios that must be followed; if not properly followed, various issues can occur, such as no cure or soft cure, as well as high exotherm during reaction, which can cause shrinkage.
Mix ratios are expressed by weight, volume, or PHR (parts per hundred). The ratio by weight and the ratio by volume are often different due to variations in density between resins and catalysts. Measurements by weight are more accurate, however, and are generally preferred over volumetric proportioning. When estimating the amount of mixed material, it’s important to know the pot life of the product in order to avoid wasting material.
Encapsulants & Potting Compounds from RMC
Robert McKeown Co., Inc., a family-owned fabricating distributor of engineered materials and electronic potting compounds, has been proudly serving clients for over 80 years. Our expert staff specializes in a wide range of protective solutions for electronics, and we work closely with all our clients to ensure products are tailored to their unique needs.
To learn more about Dow ’s electronic potting compounds and other adhesive products from manufacturers like Henkel, contact us or request a quote today.
(10) Silicones and Electronics Long-term, reliable protection of sensitive circuits and components is becoming more important in many of today’s delicate and demanding electronic applications. Silicones function as durable dielectric insulation, as barriers against environmental contaminants and as stress-relieving shock and vibration absorbers over a wide temperature and humidity range. In addition to sustaining their physical and electrical properties over a broad range of operating conditions, silicones are resistant to ozone and ultraviolet degradation, have good chemical stability and are available in a variety of useful forms as conformal coatings, encapsulants and adhesives. Dow’s broad range of general purpose and specialty ...
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Gels are a special class of encapsulants that cure to an extremely soft material. They are used to provide high levels of stress relief to sensitive circuitry. Gels perform many important functions in electronics. Their major job is to protect electronic assemblies and components from adverse environments by:
Functioning as dielectric insulation
Protecting the circuit from moisture and other contaminants
Relieving mechanical and thermal stress on components
Dow offers a line of standard gels, a line of low-temperature gels for applications requiring low-temperature performance. A line of toughened gels for use where chemical adhesion and dimensional stability are required, and a line of specialty gels ...
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Ensuring that electronics products function as they are designed to is just one piece of the materials solution Henkel delivers. Protecting printed circuit boards and electronic assemblies from thermal cycling and adverse environmental conditions is the other critical component for product durability and reliability. Under the leading Hysol® and Stycast™ brands, Henkel offers several PCB protection products to minimize external product stress and maximize performance. Our portfolio of conformal coatings keeps moisture, humidity and other adverse conditions from deteriorating printed circuit boards used in harsh marine, automotive, aerospace and consumer electronics applications. Henkel also strives to keep environmental ...
(5) Selecting the best catalyst A catalyst determines many of the final properties of a STYCAST system. It's selection is as important as that of the resin as it has a significant influence on final cured hardness, mixed viscosity, temperature capabilities and physical properties. Understanding viscosity Viscosity is the measure of the internal resistance of friction when a material moves against itself. It is typically measured using a rotating spindle instrument (viscometer). The amount of force required to turn the spindle (torque) at a selected speed (rpm) is measured. A simple calculation converts this internal resistance to viscosity. Thicker materials equates to higher torque values, hence, higher viscosities.
Specialty Materials for Electronic Assembly
