High-performance bonding. Dow DOWSIL 7091 Adhesive/Sealant Black is a one-component, non-slumping silicone paste used for applications that require a durable, flexible bond, such as glass to plastic, glass to metal, painted steel, ceramics, and aluminum. It offers easy application, an alkoxy cure system, high performance, and unprimed adhesion.
Where it excels. 7091 is a high-performance neutral-cure silicone adhesive/sealant designed for applications that demand a strong but flexible bond, such as bonding materials with differing thermal expansion rates (e.g., glass or metal to plastics). It can also be used as a formed-in-place gasket (FIPG) material.
Unprimed adhesion and cure. It gives unprimed adhesion to commonly used materials including enameled and painted steel, aluminum, ceramic, and glass, as well as certain engineering plastics. As a neutral alkoxy-cure system, it cures at room temperature upon exposure to moisture in the air, reaching a depth of about 2 mm in 24 hours at 50% relative humidity.
Verified properties. Distributor data lists 7091 as multi-purpose, with a temperature range of -55 to +180°C; a skin-over time of near 15 minutes; tack-free time of around 28 minutes; a durometer of about 37 Shore A; tensile strength of about 2.5 MPa; and elongation of around 680%. All surfaces must be clean and dry; a primer is recommended for maximum adhesion. Review the Safety Data Sheet before use.
It is a one-part, high-performance neutral-cure silicone adhesive/sealant for durable, flexible bonds with glass, plastic, metal, painted steel, ceramics, and aluminum. It suits bonding materials with differing thermal expansion rates and can also serve as a formed-in-place gasket material.
Does 7091 need a primer?
7091 gives unprimed adhesion to many common materials, including enameled and painted steel, aluminum, ceramic, glass, and certain engineering plastics, so it often bonds without a separate primer. For maximum adhesion, Dow recommends a primer, and all surfaces must be clean and dry first.
What is a neutral (alkoxy) cure, and why does it matter?
A neutral alkoxy cure releases a milder by-product than acetoxy sealants (no vinegar-like acetic acid), making 7091 gentler on sensitive metals and electronics. It cures at room temperature upon exposure to air moisture, reaching a depth of about 2 mm in 24 hours at 50% relative humidity.
What temperature range does 7091 handle?
Distributor data lists a service range of -55 to +180°C, so the cured sealant stays flexible and functional across a wide span of hot and cold conditions. That range supports bonding assemblies exposed to temperature fluctuations; confirm the limits for your specific application in the datasheet.
What makes 7091 good for dissimilar materials?
Its strong but flexible bond accommodates the different rates at which materials like glass, metal, and plastic expand and contract with temperature. With high elongation (around 680% per distributor data), it flexes with the joint rather than cracking, maintaining a durable seal between dissimilar substrates.
