3M 280
Harmonization Code : 3907.30.00.40 | Epoxy Mold Compounds containing by weight more than 70 % silicon dioxide

Main features
- Low-Viscosity Fine-Wire Impregnation
- Semiflexible Cured Performance
- Class F Electrical Insulation
Product Description
3M Scotchcast Electrical Resin 280 is an unfilled, two-part epoxy liquid resin for oven-cured impregnation, potting, and encapsulation of electrical components. A 2:3 weight ratio or 37:63 volume ratio produces a typical mixed viscosity of 4,000 cP at 23 deg C for wetting and fine-wire penetration. After cure, the semiflexible Class F material has typical 85% elongation, 65 Shore D hardness, and electric strength of 14.8 kV/mm (375 V/mil) on a 3.175 mm (1/8 in) specimen. Its application range includes coils, transformers, strain-sensitive circuitry, modules, and other electrical or electronic assemblies requiring moisture and thermal-shock resistance.
Key features
- Low-viscosity impregnation: Typical mixed viscosity is 4,000 cP at 23 deg C for wetting fine-wire coil structures.
- Semiflexible cured response: Typical cured elongation is 85% with 65 Shore D hardness.
- Class F electrical performance: The resin is rated to 155 deg C and has typical electric strength of 375 V/mil under the stated sample condition.
Applications
Applications include impregnation, potting, and encapsulation of coils, transformers, strain-sensitive circuitry, modules, and electrical or electronic components.
TDS, SDS & Technical Documents
Technical Specifications
General Properties
Mechanical Properties
Other Properties
Additional Information
As-supplied / before-processing properties
Handling values are typical; component values and mix-ratio bases remain separated.
| Property | Value | Unit | Method / condition |
|---|---|---|---|
| Mix ratio by weight (A:B) | 2:3 | - | Before processing |
| Mix ratio by volume (A:B) | 37:63 | % | Before processing |
| Part A initial viscosity | 12,500 | cP | Typical at 23 deg C |
| Part B initial viscosity | 2,500 | cP | Typical at 23 deg C |
| Mixed initial viscosity | 4,000 | cP | Typical at 23 deg C |
| Density (A / B) | 1.15 / 1.01 | kg/L | Typical |
| Gel time | 20 | min | Typical at 121 deg C |
| Cure guide | 2 to 3 h / 6 to 8 h / 24 h | - | 120 deg C / 95 deg C / 75 deg C |
Final-state / after-processing properties
Cured properties are typical and not recommended for specification purposes.
| Property | Value | Unit | Method / condition |
|---|---|---|---|
| Cured color | Clear amber | - | Typical |
| Specific gravity | 1.08 | - | Typical; cured |
| Hardness | 65 | Shore D | Typical |
| Compressive strength | 2,400 | psi | Typical; 10% compression |
| Tensile strength | 1,950 | psi | Typical |
| Elongation at break | 85 | % | Typical |
| Electric strength | 375 (14.8) | V/mil (kV/mm) | Typical; 1/8 in (3.175 mm) sample |
| Moisture absorption | 0.5 | % weight gain | Typical; 240 h at 96% RH |
| Volume resistivity | 1 x 10^15 | ohm-cm | Typical at 23 deg C |





















