H.B. Fuller FH8731

H.B. Fuller FH8731 is a one-part epoxy potting material designed for the encapsulation of electronic parts. It features easy handling due to its one-part formulation, good stability, and fast curing at medium temperature. It is typically used for the encapsulation and protection of electronic parts.

Chemical FamilyEpoxides, Epoxy & Epoxy Derivatives

Product Type1K (1 component) Adhesive, Potting Compound, Reactive Adhesive

Application AreaElectronic Components, Encapsulant, Printed Circuit Boards

FeaturesEasy To Apply, Excellent Flowability, Fast Curing, Good Stability, High Reliability

Technical Data Sheet

Enhanced TDS

Identification & Functionality

Features & Benefits

Features and Benefits
  • 1K and no need mixing
  • Fast curing
  • Good storage stability
  • High flow ability and good reliability

Applications & Uses

Typical Applications

Encapsulation and protection of electronics parts.

Directions for Use

1. Do not open the package before complete the thawing.
2. Thawing to room temperature (25°C) before using.
3. Seal any remaining material and store immediately at 2-8℃.
4. Preheating temp. to 30-45℃.


Physical Form
Black liquid
Electrical Properties
ValueUnitsTest Method / Conditions
Dielectric Constant (at 1KHz)3.3/0.018
Dielectric Constant (at 100KHz)3.3/0.02
Volume Resistivity4.1 x 10¹⁶Ω.cm
Surface Resistivity1.3 x 10¹⁶ohm
Dielectric Strength16.2kV/mm
Cured Properties
ValueUnitsTest Method / Conditions
Hardness87.0Shore D
Glass Transition Temperature129.0°C
Coefficient of Thermal Expansion (Alpha 1)58.0m/m.°C
Coefficient of Thermal Expansion (Aplha 2)185.0m/m.°C
Water Absorption(24h)0.06%
Uncured Properties
ValueUnitsTest Method / Conditions
Viscosity (Brookfield, spindle 7, 10 rpm)36400.0mPa.s
Pot Life3.0months

Technical Details & Test Data

Recommend Curing Profile

150℃ 20 min。
It depends on the heating efficiency and the thickness of PCB and size of die. We suggest to adjust curing temperature and curing time according to heating device and adherent.

Packaging & Availability

Regional Availability
  • Africa
  • Asia Pacific (Excluding Russia)
  • Europe (Excluding Russia)
  • India
  • Latin America
  • Middle East
  • North America

Storage & Handling

Storage Conditions

FH8731 is supplied in 500ml/barrels
It should be stored in 2-8°C refrigerator.
Shelf life is 12 months from date of manufacture.