ABLESTIK 281
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
- Non-Sag Placement Control
- 1 x 10^15 ohm-cm Volume Resistivity
- 55 to 180 deg C Service Range
Product Description
LOCTITE® ABLESTIK 281 BK is a one-component, heat-cured epoxy adhesive formulated for assembly applications requiring thermal conductivity and electrical insulation. The black, thixotropic, non-sag paste is documented for bonding metals, glass, and plastics and provides controlled placement with minimal flow. Guideline cure schedules range from 4 hours at 80°C to 15 minutes at 180°C. Typical cured properties include thermal conductivity of 1.4 W/(m·K), volume resistivity above 1 × 1015 ohm-cm at 25°C, and an operating-temperature range of -55 to 180°C.
Key features
- Thermally conductive and electrically insulating: Typical cured thermal conductivity is 1.4 W/(m·K), with volume resistivity above 1 × 1015 ohm-cm at 25°C.
- Thixotropic, non-sag paste: Supports controlled adhesive placement with reduced flow during assembly.
- Wide heat-cure window: Guideline schedules include 4 hours at 80°C, 1 hour at 120°C, 30 minutes at 150°C, or 15 minutes at 180°C.
Applications / Suitable for
- Assembly bonding
- Applications requiring thermal conductivity and electrical insulation
- Bonding metals, glass, and plastics
TDS, SDS & Technical Documents
Technical Specifications
General Properties
Thermal Properties
Chemical Properties
Electrical Properties
Additional Information
As-supplied / before-processing properties
Typical physical, storage, and guideline cure information for the adhesive before final processing.
| Property | Value | Unit | Method / condition |
|---|---|---|---|
| Technology | Epoxy | — | One-component, heat-cured adhesive |
| Appearance | Black thixotropic paste | — | As supplied |
| Density | 2.3 | g/cm³ | TDS typical value; SDS reports specific gravity of 2.35 |
| Shelf life | 3 | months | At 25°C, from date of manufacture |
| Recommended cure schedule | 4 | hours | At 80°C; guideline recommendation |
| Alternative cure schedules | 1 hour, 30 minutes, or 15 minutes | — | 1 hour at 120°C, 30 minutes at 150°C, or 15 minutes at 180°C; guideline recommendations |
| Optimal storage | 25 | °C | Store unopened in a dry location; SDS states storage at or below 25°C |
After-processing / final-state properties
Typical cured thermal, electrical, mechanical, moisture-exposure, and outgassing properties. Values are reference data and are not product specifications.
| Property | Value | Unit | Method / condition |
|---|---|---|---|
| Operating-temperature range | -55 to 180 | °C | Documented product range |
| Hardness | 88 | Shore D | Cure condition and test method not stated |
| Coefficient of thermal expansion | 32.4 | ppm/°C | TMA |
| Thermal conductivity | 1.4 | W/(m·K) | ASTM D2214 |
| Water absorption | 0.06 | % | After 24-hour boil |
| Volume resistivity | >1 × 1015 | ohm-cm | At 25°C; test method not stated |
| Total mass loss | 0.35 | % | TML per NASA Reference Publication 1124; sample cured 5 hours at 80°C |
| Collected volatile condensable material | 0.06 | % | CVCM per NASA Reference Publication 1124; sample cured 5 hours at 80°C |
| Flexural strength | 62 (9,000) | N/mm² (psi) | ASTM D790 |
| Compressive strength | 83 (12,000) | N/mm² (psi) | Test method not stated |
| Tensile lap shear strength — aluminum to aluminum at 25°C | 13.8 (2,000) | N/mm² (psi) | Surface preparation, bondline, cure condition, and test method not stated |
| Tensile lap shear strength — aluminum to aluminum at 120°C | 9 (1,300) | N/mm² (psi) | Surface preparation, bondline, cure condition, and test method not stated |





















