DOWSIL™ EI-2888 Primerless Silicone Encapsulant Kit

DOWSIL™ EI-2888 Primerless Silicone Encapsulant Kit

DOWSIL™ EI-2888 Primerless Silicone Encapsulant Kit is a two-part, 1:1 mix ratio, optically clear, self-priming silicone encapsulant designed for potting rigid and flexible PCB assemblies in LED lighting, high ingress protection luminaires, explosion proof luminaires, and outdoor displays. It provides 2700 mPa.s mixed viscosity and 8 h gel time at 22°C, giving engineers a practical starting point for evaluating optical protection, electrical insulation, stress relief, and environmental exposure requirements.

Review substrate adhesion, cure schedule, optical path, potting depth, and exposure profile before qualification.

Key features

• Optically clear system: 94% light transmission at 450 nm and 95% at 760 nm, measured at 5 mm by ASTM D 1003.
• Self-priming adhesion: formulated to develop adhesion to many common substrates without primer, with substrate-specific testing required.
• Low mixed viscosity: 2700 mPa.s mixed viscosity can help support pour, flow, and needle dispense processing.
• Soft cured profile: 60 Shore 00 after 21 days at 22°C can help support low-stress encapsulation.
• Agency recognition: UL 94 HB and UL 746C f1 recognition support review for flame and outdoor-use requirements where applicable.

Processing summary

Mixing setup

Mix Part A and Part B thoroughly before dispense. Automated metered mixing can help support ratio control in production, while manual mixing should be evaluated for air entrapment and repeatability.

Void control

Where practical, dispense under vacuum. If vacuum dispensing is not available, evacuate the assembly after dispense, especially when the PCB or housing contains small voids.

Surface preparation

Apply to clean and dry substrates. Low-surface-energy materials, release agents, oils, greases, oxide films, or other contamination can affect adhesion and should be checked during qualification.

Cure review

Adhesion develops during cure and increases toward full cure at room temperature. Confirm handling time, cure time, and minimum acceptable properties on the actual assembly.

Qualification note

General adhesion statements are not possible across all substrates. Use lap shear, peel, or assembly-level testing to confirm adhesion, cure schedule, and compatibility with the intended substrate stack.

Storage and handling, per technical data sheet

Special precautions should be taken to keep moisture from contacting the product. Keep containers tightly closed, minimize headspace, and purge partially filled containers with dry air or nitrogen where appropriate. Store in the original packaging with the cover tightly attached and use the product by the Use Before date on the label.

Product proposition video

Review the Dow product proposition video for an overview of how DOWSIL™ EI-2888 is positioned for LED protection and optical performance.

Primerless encapsulant webinar

Review the Dow webinar for additional context on primerless silicone encapsulation in lighting and outdoor display applications.

• Multiple packaging sizes are available.
• Store in original packaging with the cover tightly attached.
• Keep containers tightly closed and minimize headspace.
• Use by the Use Before date shown on the product label.

• Substrate stack and surface condition.
• Potting depth, cavity geometry, and optical path.
• Dispense method, mix method, and cure constraints.
• Operating temperature, humidity, UV, and water exposure profile.

To evaluate DOWSIL™ EI-2888 for your assembly, share the substrate stack, potting depth, dispense method, cure limits, optical path, operating temperature range, environmental exposure, and any UL or outdoor-use requirements.