RTV615

Reference: GEE38079

INVISISIL™ RTV615 – Optically Clear, Two-Component Addition-Cure Silicone for Precision Electronics Encapsulation

INVISISIL™ RTV615 is a clear, colourless, addition-cure silicone rubber compound engineered for high-clarity potting and encapsulation of sensitive electronic assemblies. Supplied in matched 10:1 by weight kits (Part A: base, Part B: curing agent), RTV615 cures at room temperature or with mild heat to form a high-strength, transparent elastomer that allows for visual inspection, component identification, and field repair without compromising protection.

With a low mixed viscosity (4,000 cP) and excellent flow characteristics, RTV615 penetrates complex geometries and delicate components, providing superior electrical insulation, shock absorption, and environmental sealing against moisture, dust, ozone, and chemicals. Its optical clarity and reversion resistance make it ideal for solar cells, LED modules, sensors, and other applications where visual access and long-term reliability are essential.

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Key Features

Optically clear, colourless cure – enables visual inspection and easy troubleshooting
10:1 mix ratio by weight – compatible with manual or automated dispensing
Low mixed viscosity (4,000 cP) – excellent flow for intricate potting and deep-section encapsulation
Addition-cure chemistry – no solvents, no by-products, non-exothermic
Wide service temperature range: –60°C to 204°C (–75°F to 400°F)
High tensile strength (920 psi) and 120% elongation for mechanical durability
Reversion and hydrolytically stable – maintains performance in high-humidity, high-temperature environments

Typical Applications

Potting of solar cells and photovoltaic assemblies (maximises light transmission)
Encapsulation of LEDs, sensors, and fibre-optic components requiring optical clarity
Protection of PCBs and electronic modules where visual ID or repairability is needed
Aerospace and industrial systems requiring long-term environmental sealing with transparency

Technical Notes

Cure options: Room temperature: 6–7 days for full properties, and Accelerated: 1 hour at 100°C or 15 minutes at 150°C
Refractive index: 1.406
Dielectric strength: 19.7 kV/mm (500 V/mil)
Volume resistivity: 1.8 × 10¹⁵ Ω·cm
Shore A hardness: 44
Linear shrinkage: 0.2%
Primer required for adhesion to non-silicone substrates (e.g., SS4120 for invisible bonding, SS4155 for general use)

Processing Recommendations

Mix 10 parts A (clear base) + 1 part B (clear curing agent) by weight in a clean container (4–5× material volume)
Stir thoroughly and degas under 29 in. Hg vacuum to eliminate entrapped air
Avoid contamination from sulfur-, nitrogen-, tin-, or PVC-based materials (e.g., latex gloves, sulfur-cured rubbers), which can inhibit cure.