Water Clear Low Viscosity Silicone Potting Compound 10:1 RTV-2 Silicone Encapsulant for Optical Sensor Photodiode

HN-8808A/B is a two-component condensation-cure (tin-catalysed) RTV-2 silicone potting compound mixed at 10:1 by weight. The base flows at 2200-2600 mPa·s and the curing agent at 20-30 mPa·s, giving low-viscosity deep-fill penetration into narrow optical housings and tall cavities before curing at room temperature to a water-clear 0.94 ± 0.02 g/cm³ elastomer. Potted photodiodes, optical sensors, LED emitters and solder joints remain visible for 100% optical and visual inspection. Cured properties include ≥ 14 kV/mm dielectric strength, dielectric constant ≤ 3.0, elongation at break ≤ 100%, low-stress shrinkage, waterproof and moisture-proof protection, a −50 °C to 200 °C service range and primer-free adhesion to aluminium without corrosion of sealed parts.

• Low viscosity 2200-2600 mPa·s for deep fill – the low-viscosity mixed system penetrates narrow gaps, fine lead frames and tall optical cavities, reducing voids and incomplete encapsulation in photodiode and sensor housings.
• Water-clear cure for optical inspection – the transparent elastomer lets light pass through the potting, so brightness, light output and solder joints can be verified without destructive teardown.
• Low density 0.94 ± 0.02 g/cm³ – the unfilled low-density formula stays suspended in tall cavities, so no heavy filler settles during the 8-24 hour cure and depth protection remains uniform.
• Low-stress cure on sensitive optical dies – condensation cure generates no exotherm and only small chemical shrinkage, so temperature-sensitive photodiode dies, lenses and wire bonds are not stressed.
• Dielectric constant ≤ 3.0 – low Dk keeps signal delay and loss low for optical sensor drivers, high-speed digital boards and RF modules.
• Dielectric strength ≥ 14 kV/mm – electrical insulation for sensor boards, LED drivers and waterproof power supplies.
• Elongation at break ≤ 100% – the elastic transparent skin absorbs thermal movement and vibration without cracking or delamination from the housing.
• Primer-free adhesion to aluminium – bonds directly to aluminium substrates and heat sinks without primer and without corrosion of sealed metal parts.
• Wide −50 °C to 200 °C service range – stable clarity and elasticity from cold outdoor installation to lamp and power-supply heat loads.
• 10:1 mix ratio and room-temperature cure – 8-24 h full cure at 25 °C, optional post-cure at or below 60 °C only after initial set; 22 kg and 11 kg sets suit workshop and pilot production.

Values are measured at 25 °C and 50-60% RH after the recommended cure schedule and are for reference only; actual performance may vary with application conditions.

• Pre-mix – stir Component A so any settled filler is redispersed, and stir Component B (curing agent) until homogeneous.
• Weigh – weigh A and B at exactly 10:1 by mass on a precision scale; keep A and B stored separately in a clean, dry area.
• Mix – mix until the colour is uniform and scrape the walls and bottom. Do not prepare very large batches by hand, because fluidity drops as curing starts; cure is faster in summer and slower in winter.
• Degas – vacuum degas to remove entrapped air before potting; the low mixed viscosity releases bubbles quickly.
• Pot – pour into the clean, dry device and ensure complete coverage; protect the device surface and mixing container.
• Cure – allow room-temperature initial cure, then full cure in 8-24 h at 25 °C. Optional post-cure heating must not exceed 60 °C and may only be applied after initial cure.

Critical handling notes: the freshly mixed 10:1 compound must not be heated to accelerate cure – gentle heating at or below 60 °C is allowed only after initial set. Do not fully seal the potted device or heat above 100 °C before the curing mass has released its small molecules; if complete sealing is required, seal after 3 days in summer or 7 days in winter, and keep the work area ventilated.

HN-8808A/B is specified for transparent, low-viscosity, waterproof and insulating encapsulation in the following assemblies:

photodiodephototransistorphotoelectric sensorproximity optical sensoroptical sensor modulelight guideLED chipimage sensor boardlens holdercamera modulesensor windowlaser diode package

display module edge sealingindicator lampbacklight unittouch panel framedigital display board

LED driverLED power supplylamp and luminairelighting accessorywaterproof power supplyadapter and charger boardoutdoor power module

household appliance control boardelectrical appliance modulesmall power board

automotive electronic modulelamp control boardbody control boardsensor modulealuminium substratealuminium heat sinkmetal-core PCB

PCBAconnectorterminal blockrelaytemperature and humidity sensor boardcontroller boardinstrument modulemedical diagnostic instrument board

• Standard kits – 22 kg per set (Component A 20 kg + Component B 2 kg) or 11 kg per set (Component A 10 kg + Component B 1 kg).
• Containers – Component A in 20 kg or 10 kg iron or plastic drums, Component B in 2 kg or 1 kg plastic bottles.
• Documentation – TDS, MSDS and RoHS declaration issued with every shipment.
• Storage – below 25 °C in original tightly sealed containers, protected from sunlight, moisture and heat; reseal immediately after opening.
• Shelf life – 6 months unopened and properly sealed, best used within 3 months.
• Transport classification – non-dangerous goods (general chemicals); handle with care to prevent leakage and keep away from rain.
• Supply capacity – 50 tons per month with OEM and private label service.

Shenzhen Hanast New Materials Co., Ltd. manufactures liquid silicone materials for electronic potting, thermal management and mould making, supplying OEM and private label programmes worldwide. Every lot ships with TDS and MSDS documentation and is RoHS compliant. TDS reference: HANAST-TDS-027 Rev.1 (2024-08-31).