LOCTITE 266
Harmonization Code : 3506.10.00.00 | 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

Main features
- Oil-Tolerant Threadlocking Application
- High-Strength Thread Retention
- Thixotropic Application Control
Product Description
LOCTITE® 266™ is a high-strength, high-temperature anaerobic threadlocking adhesive designed for permanent locking and sealing of threaded fasteners. The acrylic-based formulation cures in the absence of air between closely fitting metal surfaces, preventing loosening and leakage caused by vibration, shock and dynamic loads. LOCTITE 266 is specifically engineered for heavy-duty assemblies such as transmission fasteners, construction equipment, railroad components and other applications exposed to elevated temperatures and severe service conditions. The oil-tolerant, surface-insensitive formulation delivers reliable performance on a broad range of metal substrates, while its thixotropic consistency minimizes migration after application and ensures precise placement during assembly.
Key Features & Benefits
- High-strength threadlocker for permanent fastener retention.
- Designed for elevated temperature and heavy-duty applications.
- Resists vibration, impact loads and dynamic stress conditions.
- Oil-tolerant and surface-insensitive formulation.
- Thixotropic consistency reduces migration after application.
- Suitable for construction, transportation and industrial equipment assemblies.
- Fluorescent under UV light for inspection and quality verification.
Recommended Applications
- Transmission and drivetrain fasteners.
- Construction and heavy equipment assemblies.
- Railroad and transportation equipment.
- Permanent locking of threaded bolts, studs and nuts.
- Applications exposed to vibration, shock and elevated temperatures.
TDS, SDS & Technical Documents
Technical Specifications
General Properties
Physical Properties
Additional Information
As-Supplied / Before-Processing Properties
| Property | Value | Unit | Condition |
|---|---|---|---|
| Technology | Acrylic | — | Anaerobic threadlocker |
| Chemical Type | Dimethacrylate Ester | — | One-component |
| Color | Red-Orange | — | Opaque liquid |
| Strength Classification | High | — | Threadlocking adhesive |
| Fluorescence | Positive | — | Visible under UV light |
| Specific Gravity | 1.19 | — | 25°C |
| Viscosity | 7,000 - 11,000 | mPa·s | Brookfield RVF, spindle 3, 2 rpm, 25°C |
| Viscosity | 2,500 - 5,000 | mPa·s | Brookfield RVF, spindle 3, 20 rpm, 25°C |
| Flash Point | >100 | °C | See SDS |
After-Processing / Final-State Properties
| Property | Value | Unit | Condition / Method |
|---|---|---|---|
| Breakaway Torque | 30 | N·m | M10 black oxide bolts and steel nuts, 24 h @ 22°C |
| Prevail Torque | 9 | N·m | M10 black oxide bolts and steel nuts, 24 h @ 22°C |
| Breakloose Torque | 33 | N·m | ISO 10964, pre-torqued to 5 N·m |
| Maximum Prevail Torque | 9 | N·m | ISO 10964, pre-torqued to 5 N·m |
| Breakaway Torque After Heat Exposure | ≥11.3 | N·m | After 24 h cure + 2 h @ 260°C, tested hot |
| Prevail Torque After Heat Exposure | ≥2.8 | N·m | After 24 h cure + 2 h @ 260°C, tested hot |
| Heat Resistance | Up to 260 | °C | Heat aging and elevated-temperature performance |
| Environmental Resistance | Excellent | — | Resists oils, gasoline, brake fluid, ATF, water/glycol and solvents |





















