Traditional silicone cures over hours as moisture works in from the surface, which limits throughput and leaves thick sections soft for a long time. UV curable silicone fixes in seconds under a lamp, combining silicone’s flexibility and temperature range with a production-friendly cure.

What UV Curable Silicone Is

UV curable silicone is a one-part silicone that polymerizes rapidly when exposed to UV light. Many grades are dual cure: the UV mechanism fixes the exposed material in seconds, and a secondary moisture-cure mechanism finishes any shadowed silicone over the following hours. This gives fast handling strength without leaving deep or hidden sections uncured.

It keeps the core silicone properties:

• Wide service temperature, commonly from about -55 C to 200 C or higher.
• High flexibility and elongation, so seals and coatings move with the substrate.
• Vibration and shock damping from the low-modulus cured rubber.
• Moisture, ozone, and UV resistance for outdoor and harsh-environment service.
• Good dielectric strength for electrical sealing and coating.

Advantages Over Standard Silicone

• Seconds to handling strength. Assemblies move down the line immediately instead of curing on a rack.
• On-demand cure. The silicone stays workable until the light fires, so beads can be inspected and parts positioned first.
• Consistent through-cure. The UV mechanism sets the bulk immediately rather than waiting for moisture to diffuse through a thick section.
• Lower work-in-process. No large curing area or long dwell between stations.
• Solvent-free. One-part, 100 percent solids chemistry with minimal shrinkage.

Applications

• Form-in-place gaskets (FIPG): a silicone bead dispensed onto a housing flange and cured in place, replacing die-cut gaskets with an exact-fit seal.
• Sealing and potting: environmental seals around connectors, enclosures, and lighting assemblies, and low-stress potting of components that need a compliant surround.
• Conformal coating: a flexible protective film on boards that run hot or vibrate.
• Bonding: joining glass, metal, and many plastics where a flexible, temperature-tolerant bond line is needed.
• Strain relief: compliant fillets where wires and connectors meet a board or housing.

Choosing the Right Grade

Cure format. Confirm whether the grade is UV-only or UV plus moisture. UV-only grades need full light access to every part of the deposit; dual-cure grades tolerate shadowed geometry. Match this to the joint or bead design.

Viscosity and flow. Self-leveling grades suit thin coatings and filling; non-slump grades hold a tall gasket bead on a vertical or inverted flange. Choose from the application geometry.

Hardness and modulus. Softer grades give better sealing compression set and vibration damping; firmer grades give more structural holding. Decide from whether the job is primarily sealing or bonding.

Service temperature and environment. Match datasheet limits for temperature range, and for ozone, UV, and chemical exposure in outdoor or industrial service.

Substrate adhesion. Silicone is selective. Confirm adhesion to the specific substrate, and use a primer where the datasheet calls for one. Many plastics need surface treatment.

Thermal expansion. Silicone’s flexibility usually absorbs expansion mismatch, but an aggressively cycled joint between very dissimilar materials can still fatigue. Our explanation of how CTE mismatch causes bond failure covers the mechanism.

Incure’s Pyra-Sil UV silicone range covers this ground, including one-part UV and UV/moisture grades that cure in as little as 10 seconds for form-in-place gasketing, coating, and sealing on electronics and industrial assemblies, and grades with PCBA coating properties such as moisture and arcing resistance. Grade selection follows from cure format, viscosity, and the service environment.

Email Us with your bead or bond geometry and service temperature for a grade recommendation.

Curing Equipment

• Flood lamps cure gasketed housings and coated boards with a uniform dose. See matching a UV LED flood lamp curing area to intensity.
• Conveyor systems cure inline at production rate. See matching a conveyor lamp head to line speed and part width.
• Our overview of selecting a UV lamp for resin curing covers output and wavelength matching.

Verify dose with a radiometer. On dual-cure grades, allow the moisture mechanism time to complete in shadowed areas before the assembly sees service.

Applications by Industry

• Automotive and transit electronics: sealed control modules, lighting assemblies, and sensor housings under heat and vibration.
• Industrial equipment: enclosure and connector seals in dusty or damp plants.
• Renewable energy: outdoor inverter and junction-box sealing.
• Appliances and lighting: flush glass and lens sealing, and gasketing on housings.
• Aerospace and marine: flexible seals and coatings resisting shock, salt fog, and wide temperature swings.

Application Guidelines

1. Clean and prime. Remove contamination and apply the specified primer. Silicone adhesion failures are usually surface-preparation failures.
2. Dispense a consistent bead. Use a valve and dispensing tip sized to the flange width; a programmed path gives a repeatable seal.
3. Cure with full light access. Position the lamp so the whole bead is exposed; rely on the secondary cure only where shadowing is unavoidable.
4. Allow secondary cure to finish. Do not compress a gasket or load a joint before the moisture mechanism has completed in hidden sections.
5. Validate compression set and adhesion. Confirm seal performance on representative parts after full cure and environmental exposure.

UV curable silicone gives manufacturers silicone’s flexibility and temperature range without its slow cure. Matching cure format and viscosity to the application, priming the substrate, and delivering a verified dose are what make it perform.

Contact Our Team for a UV curable silicone recommendation matched to your sealing or bonding job.

Visit www.incurelab.com for more information.