COOLTHERM EP-3500
Harmonization Code : 3910.00.00.90 | Silicones in Primary Forms; Others
Main features
- 3.3 W/(m K) Thermal Conductivity
- 10.4 to 12 ppm/deg C CTE
- 205 to 206 deg C Glass Transition
Product Description
CoolTherm® EP-3500 Epoxy Resin is a dark gray, highly filled epoxy resin formulated for use with CoolTherm® EP-3500 Hardener or CoolTherm® EP-2000 Hardener. The two-component systems are designed for encapsulating motor stators, transformer coils, and electrical devices requiring a rigid material with high thermal conductivity and a low coefficient of linear thermal expansion. Depending on the selected hardener, the cured system provides a typical thermal conductivity of 2.6 or 3.3 W/m·K, a glass transition temperature of approximately 205–206 °C by TMA, and electrical insulation properties.
Key features
- High thermal conductivity: Provides a typical cured thermal conductivity of 3.3 W/m·K with EP-3500 Hardener or 2.6 W/m·K with EP-2000 Hardener.
- Low thermal expansion: Delivers a typical coefficient of linear thermal expansion of 10.4–12 ppm/°C, depending on the selected hardener.
- High-temperature cured system: Provides a typical glass transition temperature of 205–206 °C by TMA.
Applications / Suitable for
- Motor stator encapsulation
- Transformer-coil encapsulation
- Electrical devices requiring rigid, thermally conductive encapsulation with low thermal expansion
TDS, SDS & Technical Documents
Technical Specifications
General Properties
Appearance
Drak Gray Paste
Appearance at room temperature.
Specific Gravity
2.98
Specific gravity (SG) is the ratio of the density of a substance to the density of a reference substance; equivalently, it is the ratio of the mass of a substance to the mass of a reference substance for the same given volume.
For liquids, the reference substance is almost always water (1), while for gases, it is air (1.18) at room temperature. Specific gravity is unitless.
Physical Properties
Viscosity
@ 60°C 10/s 9200 mPa.s
Viscosity is a measurement of a fluid’s resistance to flow.
Viscosity is commonly measured in centiPoise (cP). One cP is defined as
the viscosity of water and all other viscosities are derived from this base. MPa is another common unit with a 1:1 conversion to cP.
A product like honey would have a much higher viscosity -around 10,000 cPs-
compared to water. As a result, honey would flow much slower out of a tipped glass than
water would.
The viscosity of a material can be decreased with an increase in temperature in
order to better suit an application
Thermal Properties
Glass Transition Temperature (Tg)
205-206 °C
The glass transition temperature for organic adhesives is a temperature region where the polymers change from glassy and brittle to soft and rubbery. Increasing the temperature further continues the softening process as the viscosity drops too. Temperatures between the glass transition temperature and below the decomposition point of the adhesive are the best region for bonding.
The glass-transition temperature Tg of a material characterizes the range of temperatures over which this glass transition occurs.
Thermal Conductivity
2.6 - 3.3 W/m.K
Thermal conductivity describes the ability of a material to conduct heat. It is required by power packages in order to dissipate heat and maintain stable electrical performance.
Thermal conductivity units are [W/(m K)] in the SI system and [Btu/(hr ft °F)] in the Imperial system.
Electrical Properties
Dielectric Strength
15.4 kV/mm
Dielectric strength is measured in kV per mm and is calculated by the Breakdown voltage divided by the thickness of the tested material.
Those two properties go hand in hand and while Breakdown voltage is always thickness dependent, dielectric strength is a general material property.
As an example, the dielectric strength of Polyimide is 236 kV/mm. If we place 1mm of Polyimide between two electrodes, it will act as an insulator until the voltage between the electrodes reaches 236 kV. At this point it will start acting as a good conductor, causing sparks, potential punctures and current flow.
Volume Resistivity
1 x 10^14 Ohms⋅cm
Volume resistivity, also called volume resistance, bulk resistance or bulk resistivity is a thickness dependent measurement of the resistivity of a material perpendicular to the plane of the surface.
Additional Information
Technical properties
As-supplied / before-processing properties
Typical properties of CoolTherm EP-3500 resin and its mixed systems with CoolTherm EP-3500 or EP-2000 Hardener before cure. Values are not intended for specification purposes.
| Property | Value | Unit | Method / condition |
|---|---|---|---|
| Appearance | Dark gray paste | — | CoolTherm EP-3500 resin as supplied |
| Viscosity | 9,200 | cP | Resin at 60 °C; shear rate 10/sec |
| Specific gravity | 2.98 | — | Resin at 25 °C |
| Mix ratio by weight | 100:100 / 100:72 | Resin:hardener | EP-3500 Hardener / EP-2000 Hardener |
| Mix ratio by volume | 100:100 / 100:78 | Resin:hardener | EP-3500 Hardener / EP-2000 Hardener |
| Mixed viscosity | 8,000 / 3,800 | cP | At 60 °C; EP-3500 Hardener / EP-2000 Hardener |
| Mixed specific gravity | 2.98 / 2.88 | — | EP-3500 Hardener / EP-2000 Hardener |
| Working life | >3 / >3 | hours | At 60 °C; EP-3500 Hardener / EP-2000 Hardener |
| Shelf life | 9 | months | Resin stored at 25 °C in the original, unopened container; periodic container rotation is required to reduce hard-packed filler settling |
Technical properties
After-processing / final-state properties
Typical cured properties of CoolTherm EP-3500 resin with EP-3500 or EP-2000 Hardener. Values are listed in that order and were measured after curing for 2 hours each at 120 °C, 150 °C, 180 °C, and 210 °C. Values are not intended for specification purposes.
| Property | Value | Unit | Method / condition |
|---|---|---|---|
| Thermal conductivity | 3.3 / 2.6 | W/m·K | EP-3500 Hardener / EP-2000 Hardener; test method not stated |
| Coefficient of linear thermal expansion | 10.4 / 12 | ppm/°C | EP-3500 Hardener / EP-2000 Hardener; test method and temperature region not stated |
| Glass transition temperature | 206 / 205 | °C | TMA; EP-3500 Hardener / EP-2000 Hardener |
| Hardness | 90 / 93 | Shore D | ASTM D2240; EP-3500 Hardener / EP-2000 Hardener |
| Storage modulus | 20 / — | GPa | DMA; EP-3500 Hardener / EP-2000 Hardener; EP-2000 Hardener value not reported |
| Volume resistivity | 1 × 1014 / 1 × 1014 | ohm-cm | ASTM D257 at 25 °C; EP-3500 Hardener / EP-2000 Hardener |
| Dielectric strength | 15.4 (390) / — | kV/mm (V/mil) | ASTM D149; EP-3500 Hardener / EP-2000 Hardener; EP-2000 Hardener value not reported |
