RBC-4210 Resin


RBC-4210 epoxy resin is a thixotropic, fire retardant version of the highly filled RBC-4100 thermally conductive epoxy resin. It is designed for applications where thermal conductivity, excellent electrical insulation, high heat distortion and low shrinkage are required. This epoxy resin offers excellent resistance to filler settling during storage and may be heated to 140oF to reduce viscosity prior to adding epoxy hardener catalyst. RBC-4210 can be cured at room temperature or elevated temperatures to fit a variety of applications. Being a thermally conductive epoxy, it can be used as a heat sink for large casting or as an epoxy potting compound or encapsulant for heat generating components.


Mixed Viscosity @ 25oC, cps: Thixotropic

Shelf Life, (closed Container @ 25oC): 12 months


Color: Black
Specific Gravity @ 25oC: 1.60
Hardness, Shore D: 90
Linear Shrinkage, in./in.: 0.003
Moisture Absorption 10 Days @ 25oC, %: 0.18
Izod Impact Strength, ft. lbs./in. of notch: 0.29
Tensile Strength @ 25oC, psi: 10,000
Compressive Strength @ 25oC, psi: 25,500


Thermal Conductivity, cal/sec/cm2/oC/cm X 10-4: 30
Thermal Stability, 1000 Hrs. @ 175oC, % Wt. Loss: 0.35
Coefficient of Thermal Expansion, in./in./oC X 10-6: 27
Heat Distortion Temperature, oC: 155
Operating Temperature Range, oC : -65 to 155


Volume Resistivity @ 25oC, ohm-cm: 6×1016
Dielectric Strength, volts/mil: 480
Dielectric Constant @ 25oC, 100 KC: 5.7
Dissipation Factor @ 25oC, 100 KC: 0.018

(Note: The above properties are typical of a system cured with epoxyhardener #AB-312.)


A-110: A rigid, room temperature curing system with limited pot life and fast cure.

A-115: A resilient, low viscosity system with slightly longer pot life, that exhibits excellent resistance to thermal shock.

AB-312: Good resistance to heat, chemicals, thermal and mechanical shock, and good electrical properties at high humidity.


Weigh the desired amount of RBC-4200 epoxy resin into a clean container and combine with recommended epoxy hardener in one of the ratios shown below.

Hardener Parts by Weight
per 100 pts. Resin
Pot Life 
100 grams @ 25oC
A-110 5.7 2 hours
A-115 6 3 hours
AB-312 11 5 hours


Hardener Cure @ 25oC Cure @ 65oC Cure @ 100oC Cure @ 130oC
A-110 24 hours 2 hours
A-122 24 hours 2 hours
AB-312 6 hours 5 hours 3 hours