LOCTITE SI 5091 UV Cure Silicone Adhesive for Electronic Potting, Coating and Sealing

LOCTITE SI 5091 UV Cure Silicone Adhesive Benefits

LOCTITE SI 5091 UV Cure Silicone Adhesive combines fast light curing with flexible specialty silicone technology. The single-component format eliminates weighing, mixing, and ratio-control errors, making the product suitable for manual dispensing and automated manufacturing. Its self-leveling consistency promotes uniform cavity filling and smooth protective coatings.

Under suitable UV exposure, functional strength develops almost immediately. Henkel lists a tack-free time of no more than 20 seconds when cured at 75 mW/cm² under stated test conditions. Moisture curing begins after exposure to air and continues in areas receiving limited light. Full performance properties continue developing for approximately 72 hours at ambient conditions.

Applications for LOCTITE SI 5091 UV Cure Silicone Adhesive

The product is used for potting, coating, and sealing automotive, electronic, military, and general industrial components. Typical uses include protecting circuit assemblies, sealing sensors, coating connectors, filling electronic housings, encapsulating modules, and creating flexible barriers around parts exposed to vibration or environmental stress.

LOCTITE SI 5091 can be evaluated for glass, metals, ceramics, and compatible plastics. Its flexible cured structure is useful where rigid adhesives may transmit excessive stress to delicate parts. The material also supports leak-proof sealing and protective coating where a transparent, electrically insulating silicone layer is preferred. Users should test adhesion, cure depth, and compatibility on actual substrates before production approval.

LOCTITE SI 5091 UV Cure Silicone Adhesive Technical Properties

The uncured material is a translucent acetoxy silicone liquid with a typical specific gravity of 1.01 and non-volatile content above 95%. Published Brookfield viscosity is 4,000 to 6,000 mPa·s at 25°C. After the specified curing process, typical properties include Shore A hardness from 31 to 37, elongation of at least 75%, tensile strength of at least 0.6 N/mm², volume resistivity of 3.3 × 10¹³ Ω·cm, and dielectric breakdown strength of 18 kV/mm.

Its published service-temperature range is approximately -60°C to 180°C.

How to Apply LOCTITE SI 5091 UV Cure Silicone Adhesive

Clean all surfaces and remove grease, oil, dust, moisture, release agents, and loose contamination. Dispense the required quantity into the cavity or onto the bonding or sealing area. Assemble parts within a few minutes because moisture curing begins immediately after exposure to the atmosphere.

Henkel recommends an initial UV cure using a minimum irradiance of approximately 30 mW/cm² for about 20 seconds. Deeper sections may require increased intensity or longer exposure. Shadowed areas rely on atmospheric moisture; moisture-cure depth is limited to approximately 6 mm and requires at least 24 hours to develop. Remove excess uncured material with a suitable non-polar solvent and allow the assembly to reach full properties before demanding service.

Why Buy LOCTITE SI 5091 UV Cure Silicone Adhesive?

LOCTITE SI 5091 UV Cure Silicone Adhesive offers rapid UV processing, secondary moisture curing, high flexibility, electrical insulation, self-leveling application, and broad substrate versatility. It is a practical solution for manufacturers requiring efficient potting, coating, sealing, and elastic bonding of electronic, automotive, ceramic, glass, metal, and plastic components.

Review the official Henkel LOCTITE SI 5091 Technical Data Sheet and Safety Data Sheet before qualification or use. Explore our UV-curing silicone adhesives for additional flexible coating, potting, bonding, and sealing solutions.