Potting Compounds: A Material Selection Guide

In electronics manufacturing and assembly, potting materials are compounds that can fill and seal cavities in electronic assemblies.  By doing so, potting compounds protect components from vibration and shock.  Potting compounds can also protect devices from moisture, dust, and other contaminants that could cause corrosion or electrical failures. A range of potting compounds is available to address the unique needs of different devices, the environments in which users will operate the electronic device, and provide other special features such as flame retardance, radiation protection, or low outgassing properties for space and high vacuum applications.  Specialty Polymers & Services, Inc. makes hundreds of potting and encapsulating compounds based on a range of chemistries including epoxy, polyurethane, and silicone systems, and we can customize systems for your application.  

potting electronics

Key Benefits of Electronics Potting Compounds

In addition to guarding electrical components against shock and vibrations, some of the key benefits of potting compounds for electronics include:

  • Electrical insulation. Taking the place of air within an assembly, electronic potting material provides an additional layer of electrical insulation. They can eliminate the risk of over-voltage or arc-over in high voltage devices and prevent or contain fires when devices fail.
  • Thermal properties. Within an assembly, the heat that the electrical components generate may build up during use and lead to failure or reduced component life.  To prevent overheating, thermally conductive potting material dissipates heat within the assembly. Flexible potting materials are also able to protect electronics from thermal shock, and damage caused by internal shrinkage due to exposure to cold temperatures.
  • Resistance to moisture and chemical corrosion. Moisture within an electronic assembly could cause electrical failures, improper functioning, and lead to corrosion.  Some operating environments also expose the components to solvents, oils, fuel, and other chemicals.  Suitable potting compounds can seal out moisture and chemicals and allow the device to continue to function even fully immersed in water and specific chemicals.
  • Protection from environmental hazards. In addition to defending moisture and chemicals, potting materials protect against humidity, dust, ambient temperatures, and even pressure changes including vacuum that might damage the components.  
  • Long-lasting performance. Because potting material minimizes damage from vibration, impact, drops, and other motion, it can greatly extend the lifespan of the device. This can be crucial for applications near engines and for mobile devices where vibration and drops may occur frequently.
  • Enhanced durability. Some types of potting materials can provide protection against abrasion and sliding damage.   These are typically either tough, high tear strength elastomers or rigid, mineral filled systems. 
  • Ability to use electronics in field conditions. Potting and encapsulation protect end users from exposure to electrical current and can be formulated to meet Underwriter Laboratory (UL) standards for consumer devices.  Some compounds may actually be UL recognized and the use of UL recognized potting compounds may reduce the costs for manufacturers to have their devices UL listed.  
  • Obscuring the unique configurations and IP of the electronic product. Finally potting compounds can be formulated to be opaque and difficult to remove without destroying the electronic assemblies. This can help to protect proprietary designs and may be required to meet data storage requirements for the financial industry.  

Potting vs. Conformal Coating

Conformal coatings are materials that are applied to circuit boards and assemblies to create thin dielectric layers.  These liquid coatings conform to the shape of the electronic components on the board to create a thin (typically 5 mils or less) coating when fully cured.  Conformal coatings are available based on multiple chemistries including acrylics, epoxies, polyurethanes, silicones, and parylene.  SP&S offers most types of conformal coatings including UL listed, Mil-I-46058, and IPC-CC-830 compliant coatings.

While potting and conformal coating provide an insulating layer around electronics and protect against moisture, chemical, and vibration, each has different strengths. For applications needing high mechanical strength, abrasion resistance, thermal conductivity, or the best possible electrical insulating and chemical & environmental resistance, potting is likely the best choice. Conformal coating is typically a faster process, uses less material, and often uses flexible to semi-flexible materials so it is good for stress sensitive components.   Conformal coating is also good for applications with tight tolerances or weight limits.

electronic encapsulants potting

Potting Compound Types & Common Applications

Every potting compound offers slightly different characteristics and degrees of protection. Three popular potting compound chemistries are:

Epoxy Potting Compounds

Epoxy potting materials range from semi-flexible to rigid systems with excellent chemical and environmental resistance, high mechanical strength, excellent heat resistance, and very good insulation properties.  Some grades are suitable for long term outdoor applications, low outgassing applications, and can provide high thermal conductivity. 

SP&S’ EpoPro® Product line includes more than 200 epoxy systems that cover a wide range of applications and conform to hundreds of OEM, military, and industry specifications.  

Urethane Potting Compounds

Urethane (aka polyurethane) potting materials can provide a range of properties from very soft and flexible gels that are an alternative to silicones all the way up to stiff, rigid materials with properties similar to epoxies.  They are often used for sealing assemblies, for cryogenic applications, and for applications requiring short processing times for high productivity.  Many urethanes are cost effective and can be formulated to meet UL, NASA low outgassing, and other specialty performance requirements. 

SP&S’ Ultralane® polyurethane potting materials and Liquidweld™ sealants provide a wide range of options covering hundreds of applications and are qualified or conform to hundreds of specifications.

Silicone Potting Compounds

Silicone potting materials range from super soft gel like material up to hard rubbers.  They excel in applications requiring elasticity and flexibility and in cryogenic applications.  So they are often used for fragile or stress- sensitive assemblies. They also provide temperature resistance up to about 400F and resistance to moisture and some chemicals very well.   They are widely used in automotive applications, but specialty grades  may be required for space or high vacuum applications.  

SP&S carries silicone potting compounds from Dowsil and CHT/ Quantum Silicones.  We also offer a line of our Sil-Flex™ potting materials, and Liquidweld™ one component sealants that are very cost effective and are suitable for many common applications. 

 


Contact SP&S for Potting & Encapsulation Solutions

Choosing the right potting compound for your electronic product can drastically extend its lifespan, allow it to be used in more applications or environments, and protect your organization's intellectual property from casual investigation. At SP&S, we provide high-quality potting compounds to suit your product's unique needs. With a commitment to service, reliability, and quality, we are an ISO 9001:2015-certified company and produce numerous Mil-Spec products.

SP&S is here to help. Contact us today to start your order or request pricing details.

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