Primerless Silicone Encapsulant

The company offers a new silicone encapsulant that allows manufacturers to eliminate priming and heat curing in electrical/electronic applications, without sacrificing production speeds. The material's fast-acting, room temperature curing formulation prevents exposure of heat-sensitive components to high cure temperatures, yet the material's quick adhesion accommodates high production speeds and line output.

By eliminating the priming step typically required for good adhesion, users have the opportunity to reduce costs, simplify assembly, and cut production time. Designed for auto-dispensing and high-speed production, the new material's viscosity of 2,700 cps makes it suitable for penetrating into complex component shapes.

Sylgard 275 Primerless Encapsulant is a two-part, flowable silicone liquid that cures rapidly at room temperature to a flexible, yet durable elastomer. The solventless material exhibits no outgassing and releases no harmful by-products as a result of the curing process. Unlike some cure systems, the formulation is suitable for use in combined areas.

The new material provides excellent wetting and adhesion to help prevent voids and protect sensitive electrical/electronic devices from exposure to moisture, thermal cycling, oxidation, UV degradation, mechanical shock, and other harsh conditions. The encapsulant bonds to a wide variety of substrates, but specific testing is always recommended on the surface to be used.

The product is a platinum-catalyzed material that cures at a predictable and consistent rate, regardless of sectional thickness or degree of confinement. At room temperature, the material forms a tack-free surface within 20 minutes.

Because no post curing is required, finished components can be placed into service as soon as initial cure is complete. The product not only achieves very good adhesion within 24 hours, but the adhesive properties of the encapsulant continue to build over time.

The new material provides durable insulating properties and offers excellent protection from environmental factors. It serves as a shock and vibration absorber, with good flexibility and stress-relief over a wide temperature and humidity range.

The product retains its elastomeric properties over time, and will yield in response to thermal or mechanical movement in order to prevent damage to electrical/electronic components. Although the product is tough enough to withstand moderate impact, it can easily be repaired if the encapsulant becomes damaged.

Dow Corning Corporation, PO Box 0994, Midland, MI 48686-0994. Tel: 517-496-6000; Fax: 517-496-4586.