Robert McKeown Co., Inc. - Silicone Potting/Encapsulant Gels

Gels are a special class of encapsulants that cure to an extremely soft material. They are used to provide high levels of stress relief to sensitive circuitry. Gels perform many important functions in electronics. Their major job is to protect electronic assemblies and components from adverse environments by:

Functioning as dielectric insulation
Protecting the circuit from moisture and other contaminants
Relieving mechanical and thermal stress on components

Dow offers a line of standard gels, a line of low-temperature gels for applications requiring low-temperature performance. A line of toughened gels for use where chemical adhesion and dimensional stability are required, and a line of specialty gels for applications requiring low extractables, ultra-violet (UV) cure, or resistance to solvents and fuels. In addition, Dow offers custom gels that can be quickly tailored to meet specific application needs for properties such as color, viscosity, hardness, and cure rate.

Unit of Measure

Items	3-4170 Dow Dielectric Gel Kit	3-4680 Dow Silicone Gel Kit	527 Sylgard® A & B Silicone Dielectric Gel Clear & Red	3-4222 Dow Dielectric Firm Gel Kit	3-4241 Dow Dielectric Tough Gel Kit
Specific Gravity¹	N/A 0.97/0.96 g/cc	N/A 0.97 g/cc	N/A 0.95 g/cc	N/A 0.97 g/cc	N/A 0.97/0.98 g/cc
Type	N/A Standard Gels	N/A Standard Gels	N/A Standard Gels	N/A Toughened Gels	N/A Toughened Gels
Cure System	N/A Addition cure
Color	N/A Clear	N/A Transparent blue	N/A Clear or red	N/A Translucent green	N/A Translucent green
Viscosity [cPs or mPa·s]	N/A 475	N/A 275	N/A 475	N/A 325	N/A 400
Penetration [1/10 of mm]	N/A 65	N/A 60	N/A 45	N/A 39 Shore 00 (Measured by durometer rather than penetration.)	N/A 63 Shore 00 (Measured by durometer rather than penetration.)
Gel Hardness	N/A 85 g	N/A 90 g	N/A 120 g	N/A 270 g	N/A
Shelf Life²	N/A 12 months
Working Time	N/A > 24 h	N/A < 10 min	N/A 90 min	N/A 3 min	N/A > 60 min
Room Temperature Cure Time³	N/A	N/A 15 min/30 min	N/A 24 h/> 1 week	N/A 30 min/60 min	N/A 8 h/11 h
Heat Cure Time	N/A 3 at 150 ºC 5 at 125 ºC 9 at 100 ºC	N/A 1.5 at 125 ºC	N/A 210 at 100 ºC 35 at 150 ºC 75 at 125 ºC	N/A 1 at 125 ºC 2 at 100 ºC	N/A 2 at 125 ºC (Time to adhesion may take longer.)
Dielectric Strength	N/A 500 V/mil20 kV/mm	N/A 400 V/mil16 kV/mm	N/A 385 V/mil15 kV/mm	N/A 350 V/mil14 kV/mm	N/A 450 V/mil17 kV/mm
Dielectric Constant at 100 Hz/100 kHz	N/A 2.85/2.85	N/A 2.75/2.75	N/A 2.85/2.85	N/A 2.64/2.64	N/A 2.6/2.61
Volume Resistivity	N/A 9.50E+14 O/cm	N/A 3.60E+15 O/cm	N/A 7.00E+15 O/cm	N/A 1.00E+15 O/cm	N/A 3.30E+14 O/cm
Dissipation Factor at 100 Hz/100 kHz	N/A 0.0016/0.00007	N/A 0.0004/< 0.00006	N/A 0.002/0.0001	N/A 0.0007/0.0002	N/A 0.021/0.0002
Linear Coefficient of Thermal Expansion	N/A 425 µm/(m·ºC)	N/A 435 µm/(m·ºC)	N/A	N/A 320 µm/(m·ºC)	N/A 325 µm/(m·ºC)
¹ Cured or uncured A & B. ² Shelf life from date of manufacture for material in the original, unopened container, stored at less than 35ºC, unless otherwise noted. ³ Time to non-flow/full cure.