DOWSIL™ 7091: High-Performance Elastic Bonding and Sealing Solution for Demanding Engineering Applications

DOWSIL™ 7091 is a one-part, neutral cure (alkoxy) silicone adhesive sealant. It cures at room temperature upon exposure to moisture in the air to form a tough, durable, and flexible rubber. Designed for applications demanding a strong yet flexible bond, it effectively accommodates stress caused by differing thermal expansion rates between materials, making it an ideal choice for solving complex bonding and sealing challenges in modern manufacturing.

Offers excellent unprimed adhesion to a variety of substrates (e.g., glass, metal, ceramic, painted steel, aluminum, and many engineering plastics), resulting in 100% cohesive failure for reliable bonds. The cured product features high elongation (680%), effectively absorbing and dissipating vibration and impact energy.

The product remains stable and flexible over a wide service temperature range of -40°C to 180°C, with the ability to withstand short-term thermal cycling beyond this range. This makes it ideally suited for components exposed to extreme temperature fluctuations, such as in transportation vehicles.

It is approved for the stringent railway fire safety standard EN 45545-2​ (HL1, HL2, HL3), making it a safe and reliable choice for bonding and sealing both interior and exterior components in rail vehicles (e.g., high-speed trains, metros).

It features a paste-like, non-sag consistency for easy application on vertical surfaces. Under standard conditions (23°C, 50% RH), it typically skins over in about 15 minutes​ and becomes tack-free in approximately 30 minutes, allowing for faster processing.

Based on its outstanding properties, DOWSIL™ 7091 plays a critical role in various industries.

• High-speed rail/Metro window bonding: Bonding window glass to metal or composite car bodies, withstanding vibrations and wind pressure at high speeds while meeting fire safety standards.
• Bus body panel bonding and sealing: Serving as a weld seam sealant or adhesive for body panels, providing durable waterproofing and stress reduction.

• Industrial control cabinet sealing: Sealing cabinet doors and interfaces to provide dust and water ingress protection (IP rating), while resisting heat generated internally.
• Flexible bonding of heat sinks to components: Attaching heat sinks to sensitive electronics, offering structural bond while accommodating micro-movements from thermal expansion.

• Formed-In-Place Gasket (FIPG): Dispensed directly onto mating surfaces of machinery or engine housings to create a custom-fit gasket, offering superior sealing compared to pre-cut gaskets.
• Dissimilar material bonding: Widely used for reliably bonding materials with different coefficients of thermal expansion (e.g., glass, metal, plastic), such as in architectural facades and lighting fixture assembly.

All surfaces must be clean and dry. Degreasing with solvents like isopropyl alcohol or acetone is recommended. For low-surface-energy plastics (e.g., PP, PE), the use of DOWSIL™ 1200 OS Primer is advised for optimal adhesion.

Apply a bead to one substrate and assemble the parts. Tooling can be done before skin-over (within ~15 mins). Cure depth and time depend on ambient temperature, humidity, and bead thickness; deep sections require longer to cure fully.

DOWSIL™ 7091 is more than just a sealant; it is a comprehensive engineering solution. Combining excellent adhesion, long-term flexibility, a broad temperature range, and industry certifications, it provides engineers and manufacturers with confidence and reliability for demanding applications. Whether in high-speed trains or continuously operating industrial equipment, DOWSIL™ 7091 works diligently to ensure product integrity and safety.