Moisture Barrier Silicone

Single component, silicone elastomer coating designed to stabilize semiconductor junctions and surfaces and for the environmental protection of electronic components – used for diodes, transistors, integrated circuits, thick film and thin film microelectronic circuits modules.


  • Single component self-catalyzed system- simple and economical to use
  • Unaffected by humidity
  • Excellent electrical characteristics
  • Wide operating temperature range – -65 °C to 275 °C (continuous)
  • Useful as protective coating, encapsulant or potting

MBS Moisture Barrier Silicone

MBS, Moisture Barrier Silicone, is a medium viscosity translastic product specially processed from highly purified siloxane compounds. This product is particularly formulated to provide greater protection against humidity in electronic applications. MBS possesses self-catalyzing properties and cures as a single component system to form a tough protective coating impervious to moisture. Significantly, the additions of curing agents, catalysts or accelerators are not needed to effect the silicone polymerization. Furthermore, the coating shows good mechanical and electrical characteristics over a wide range of ambient conditions.

MBS is supplied at a viscosity of 60,000 cps ± 10%. Specific viscosities of 20,000 to 100,000 are available upon request.

Properties of MBS

Appearance White, opaque
Viscosity @ 25 °C 60,000 cps nominal
Density @ 25 °C 1.25
Cure 15 minutes @ 125 °C (minimum)
Post Cure 4 hrs. @ 150 °C (minimum)
Shelf Life (under refrigeration)
+5 °C (40 °F)
-10 °C (15 °F)
3 months
6 months
Physical Appearance White, Flexible
Density 1.3
Durometer, (Shore A) 35-40
Tensile Strength (psi) 250
Elongation (%) 150
Operation Temp. Range °C 75° to + 300° (275° cont)
Dielectric Constant (mc) 3.5
Dielectric Strength (volts/mil) 500
Dissipation Factor (mc) .001
Thermal Conductivity (cal/cm/sec/cm2/°C) 6 x 10-4
Volume Resistivity (ohm-cm @ 25 °C) > 1014
Water Absorption Nil
Bulk Resistivity (10 days @ 100% rel. humidity) 1014


MBS is recommended as a protective, moisture barrier coating for semiconductor devices and as an encapsulant for sensitive microelectronic circuits and other electronic components. MBS is applied by any convenient method and cured at 125 °C for 15 minutes followed by 4-hour cure at 150 °C. The post cure can be accelerated by heating at 250 °C for two hours or longer.