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CoolTherm™ EP-3500 Thermally Conductive Epoxy Encapsulant Contact Us to Buy

Product Information

LORD CoolTherm™ EP-3500 encapsulant is a two-component epoxy system designed for encapsulation of motor stators, transformer coils, and devices requiring a rigid, high thermal conductivity material with a low coefficient of thermal expansion. CoolTherm EP-3500 encapsulant provides high-temperature stability combined with excellent electrical insulation.

Shelf Life

Shelf life of each component is six months from date of manufacture when stored at 25°C in original, unopened container. CoolTherm EP-3500 resin must be periodically rotated within its container to maintain maximum shelf life. Settling will occur if not mixed.

Features and Benefits

Superior Heat Dissipation – typically provides 30-50°C lower motor end winding temperatures during high-power operation.

Low Viscosity – provides low viscosity for a highly-filled material; self-levels to fill voids in motor stators/rotors, transformer coils and other electrical devices.

Durable– cured material resists cracking during multiple thermal cycles from sub-zero temperatures to 200°C.

Uncured Typical Properties*

Mixed Appearance Dark Gray Paste
Mixed Viscosity, cps @ 60°C
Shear rate 10/s
Mixed Specific Gravity, @ 25°C 2.96
Gel Time, min @ 110°C 60
Working Life, hr @ 60°C >3
Cure Time, hr @ 110°C 2

Cured Typical Properties*

Volume Resistivity, ohm-cm @ 25°C 1 x 1014
Thermal Conductivity, W/mK 3.5
Coefficient of Linear Thermal Expansion, ppm/°C 10.4
Glass Transition Temperature (Tg), °C 206
Hardness, Shore D 90
Young's Modulus, GPa 20
Dielectric Strength, V/mil 390

* Data is typical and not to be used for specification purposes.
Cure schedule of 2 hours each at 120°C, 150°C, 180°C and 210°C.


Download Type Name
Download Technical Data Sheet CoolTherm EP-3500 Thermally Conductive Epoxy Encapsulant