LOCTITE SI 5699 –300 ML

LOCTITE® SI 5699 is a high-performance, flexible RTV silicone gasket sealant designed for forming reliable, leak-resistant seals on a wide range of flange applications. It is a moisture-curing silicone that cures at room temperature to form a tough, flexible rubber gasket. The product is particularly suitable for applications where resistance to oil, water and water/glycol mixtures is required.
LOCTITE SI 5699 is formulated for sealing flexible, machined and cast surfaces, and can be used on both metal and plastic components. It is especially useful for rigid flange sealing in applications such as transmissions, cast metal housings, automotive powertrain components and industrial equipment.
Key Features and Benefits
Flexible form-in-place gasket: Creates a durable rubber-like gasket that accommodates movement and thermal expansion between mating surfaces.
Excellent oil resistance: Suitable for sealing applications exposed to oils and lubricants.
Water and water/glycol resistance: Well suited for cooling-system and other applications where water/glycol exposure is expected.
Wide temperature capability: Designed for continuous operating temperatures from approximately -55°C to 200°C.
Room-temperature curing: Cures through exposure to moisture in the air, eliminating the need for heat curing.
Fast surface curing: Henkel specifies a tack-free time of approximately 30 minutes under its stated conditions.
Highly flexible: Suitable for applications requiring flexibility and vibration resistance.
Versatile substrate compatibility: Recommended for use with metal and plastic surfaces.
Grey colour: Supplied as a grey silicone sealant for industrial and mechanical sealing applications.
NSF Category P1 registered: Provides an additional qualification for applicable industrial sealing uses.
Applications
LOCTITE SI 5699 is designed for highly flexible assembly gasketing and is commonly suited to applications involving:
Automotive transmissions and powertrain components
Rigid flange sealing
Cast metal housings
Machinery and industrial equipment
Electric motors and heavy equipment
Components exposed to oil or lubricants
Water/glycol cooling-system applications
Corrosion-sensitive electrical assemblies
Metal-to-metal and metal-to-plastic flange sealing
Henkel identifies automotive aftermarket, powertrain and chassis, electric motors, heavy equipment, and data-centre-related applications among the relevant industries and market segments.
How LOCTITE SI 5699 Works
The sealant is applied directly to the mating flange or sealing surface. After application, it reacts with moisture in the atmosphere and undergoes room-temperature vulcanization (RTV). The material gradually forms a tough, flexible silicone rubber gasket that seals the joint against leakage while maintaining flexibility during service.
For optimum performance, the surfaces should be properly prepared and free from contaminants such as oil, grease, dirt and other residues before application.
Technical Highlights
Property
LOCTITE SI 5699
Product type
RTV silicone gasket sealant
Technology
Specialty silicone / oxime
Cure system
Moisture-cure RTV
Colour
Grey
Recommended substrates
Metal, plastic
Tack-free time
Approx. 30 minutes
Operating temperature
-55°C to 200°C
Key resistance
Oil, water/glycol
Application
Flexible assembly gasketing
Extrusion rate
Approx. 200 g/min
Technical values can vary with application conditions, substrate, joint configuration and packaging, so the current Henkel technical data sheet should be used for final engineering specifications.
Why Choose LOCTITE SI 5699?
LOCTITE SI 5699 is a strong choice when a flexible, oil-resistant and water/glycol-resistant silicone gasket is required. Its ability to cure at room temperature, accommodate movement and seal both machined and cast surfaces makes it suitable for demanding automotive and industrial maintenance applications. It provides a convenient alternative to conventional pre-formed gaskets where a form-in-place gasket solution is preferred.
LOCTITE SI 5699 – flexible RTV silicone gasket sealant for reliable flange sealing, with excellent resistance to oil and water/glycol and a service temperature range up to 200°C.