Loctite SI 5970 - Gasketing Sealant
Harmonization Code : 3506.91.90.99 | Prepared glues and other prepared adhesives, not elsewhere specified or included; products suitable for use as glues or adhesives, put up for retail sale as glues or adhesives, not exceeding a net weight of 1 kg ; Adhesives based on polymers of headings 3901 to 3913 or on rubber; Other ; Other
Main features
- One-Component Thixotropic RTV Silicone
- 25-Minute Tack-Free Time
- Oil-Resistant Sheet-Metal Gasketing
Product Description
LOCTITE® SI 5970™ Gasketing Sealant is a one-component, black alkoxy silicone paste developed for formed-in-place gasketing applications. The thixotropic formulation reduces migration after dispensing and cures at room temperature through exposure to atmospheric moisture. It becomes tack-free within 25 minutes at 23±2°C and 50±5% relative humidity. The sealant is specifically designed for applications requiring resistance to automotive engine oils and the ability to accommodate joint movement, including stamped sheet-metal covers such as timing covers and oil sumps.
Key features
- Thixotropic gasketing paste: Reduced liquid migration supports controlled application to flange and cover surfaces.
- Room-temperature moisture cure: The one-component system requires no mixing and becomes tack-free within 25 minutes at 23±2°C and 50±5% relative humidity.
- Automotive oil resistance: Developed for gasketing applications requiring resistance to automotive engine oils and joint movement.
Applications / Suitable for
- Formed-in-place gasketing applications
- Stamped sheet-metal covers
- Timing covers
- Oil sumps
Technical Specifications
General Properties
Mechanical Properties
Electrical Properties
Additional Information
As-supplied / before-processing properties
Typical properties of LOCTITE® SI 5970™ before cure. LMS-designated values are controlled under the referenced Loctite Material Specification.
| Property | Value | Unit | Method / condition |
|---|---|---|---|
| Chemical type | Alkoxy silicone | — | One-component RTV silicone |
| Appearance | Black paste | — | Uncured; LMS |
| Rheology | Thixotropic | — | Reduced migration after application |
| Specific gravity | 1.38–1.44 | — | At 25°C; LMS |
| Extrusion rate | 40–80 | g/min | Semco cartridge; 0.62 MPa pressure; 15 seconds; 25°C; LMS |
| Optimal storage temperature | 8–21 | °C | Store unopened in a dry location; long-term storage |
After-processing / final-state properties
Typical properties of the cured sealant and substrate-specific adhesive performance. Lap-shear specimens were cured for 21 days at 23°C and 50±5% relative humidity with a 0.5 mm gap.
| Property | Value | Unit | Method / condition |
|---|---|---|---|
| Shore hardness | 44 | Shore A | ISO 868 |
| Elongation | ≥200 | % | ISO 37; LMS |
| Tensile strength | ≥1.5 (≥278) | N/mm² (psi) | ISO 37; LMS |
| Surface resistivity | 1.4 × 1016 | Ω | IEC 60093 |
| Volume resistivity | 1.8 × 1015 | Ω·cm | IEC 60093 |
| Tensile lap shear strength on mild steel | 1.3–2.0 (190–290) | N/mm² (psi) | Cured 21 days at 23°C / 50±5% RH; 0.5 mm gap |
| Tensile lap shear strength on aluminum 2024-T3 | 0.7–1.3 (100–190) | N/mm² (psi) | Cured 21 days at 23°C / 50±5% RH; 0.5 mm gap |
