TECHSiL's Top 4 Optically Clear Potting Compounds for Electronics

Electronic and LED applications are increasing in variety and complexity which creates new challenges for protective potting compounds. Engineers must ensure that sensitive electronic components can perform in all environments whether it be indoor, underfoot, in the air, at sea, in space or underwater. Many components benefit from being encapsulated such as sensors, capacitors, resistors and transformers to protect them from mechanical shocks, moisture, chemicals and other environmental factors. Product selection is dependent on a number of factors in addition to colour, such as:

• Viscosity – can it flow into the housing and around components
• Hardness and density when cured – to give maximum protection
• Operating temperatures of cured resin
• Thermal conductivity
• Flame retardancy

The specifications for encapsulants for potting electronics, LEDs and electrical products are high, with many design engineers looking for products offering brilliant long term clarity, good protection from environmental factors, along with excellent thermal characteristics. As adhesive specialists, TECHSiL have selected a range of four of the best optically clear potting compounds for electronics designed to have, in particular, an excellent refractive index and great UV stability; perfect for potting LED lighting assemblies for maximum light transmission; potting electronic assemblies where component identification is desirable and other products where high transparency and aesthetics are important.

Momentive RTV615 Silicone

A crystal clear, low viscosity, 2-part silicone potting compound which cures at room temperature to a high strength rubber (44 shore A) with a thermal conductivity of 0.19 W/mK. It is a low viscosity, pourable liquid which remains flexible at low temperatures and up to 204 ⁰C and is used to protect components against shock, vibration and environmental hazards. Available in a variety of pack sizes.

Techsil® VT2420LV Polyurethane 

A low viscosity room temperature curing polyurethane resin designed for the potting and encapsulation of LED’s, luminaires and modules and other electronic parts. It has excellent outdoor weathering properties, curing to form a tough 70 Shore A material with good abrasion and hydrolysis resistance and a thermal conductivity of 0.25 W/mK. Supplied in easy to use twinpacks.

MG Chemicals® 832WC Epoxy

MG 832WC is an extremely hard 2 part water clear potting epoxy that cures to Shore 82D and offers extreme environmental, mechanical and physical protection for PCBs and electronic assemblies. Non yellowing on exposure to UV and high temperatures, it provides excellent electrical insulation, extremely high compressive and tensile strength and a service temperature range of -40 to 140 ⁰C.

TECHSiLl® RTV27905 Silicone Gel

A soft, adherent, clear 2-part silicone potting gel. RTV27905 is the softest gel from a wider family of similar silicone gels. It is used to provide protection from vibration and thermal or mechanical shock. TECHSiL® RTV 27905 has excellent dielectric properties and also gives protection from water and many environmental contaminants. This product is flexible down to -55°C, and suitable for use up to +200 ⁰C. Available in several pack sizes.