Epoxy Edge Sealing - Superior Moisture Protection

In many applications it is necessary to protect thermoelectric cooling modules from moisture infiltration. A moisture barrier is used to prevent a degradation in performance, or catastrophic failure, of the module due to junction corrosion or electrical short.

The most typical protection supplied by most manufacturers is a bead of silicon-based sealant, such as RTV, around the perimeter of the module. While RTV will keep droplets out, water vapor can penetrate the material and become trapped inside a thermoelectric cooler.

We use an "aircraft grade" epoxy alternative to RTV
- with much lower vapor permeability.

The dielectric, mechanical and physical properties of the two sealant types follow:

PROPERTIES SILICON RTV EPOXY
Technology One-component TRV rubber Two-component RTC rubber
Viscosity Thixotropic Non-slumping Thixotropic Non-slumping
Color White Amber
Hardness, Shore A 40 80
Elongation, % 300 90
Adhesive strength
to Al2 O3 ceramics kg/cm²
20 40
Coefficient of thermal conductivity, W/mºK 0.21 0.1280
Volume resistance, Ohm·cm 3·1014th 1·1015th
Dielectric strength, KV/mm 25 17
Dielectric Constant at 1 MHz 2.9 3.1
Dissipation factor at 1 MHz 3·10-3rd 1·10-2nd
Shrinkage, % 6.0 0.4
Operating temperature, ºC -40 ~ +180 -50 ~ +200

TE Modules manufactured with an Epoxy perimeter seal are designated with an "E" suffix
(for example: TM-127-1.4-6.0 "E").

If you have a question, please feel free to contact us.