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Reactive viscosity model

The reactive viscosity model describes the temperature, shear rate, and cure dependance of thermoset materials. This model can be used in a Reactive Molding, Microchip Encapsulation, or Underfill Encapsulation analysis.

The following equation is used for determining the viscosity of these materials: Reactive viscosity equation where:

  • eta is the viscosity (Pa. sec.)
  • gamma dot is the shear rate (1/sec.)
  • T is the temperature (deg K)
  • alpha is the degree of cure (0 - 1),
  • equation for eta zero, and
  • n, tau star, B, T subscript b, b, C subscript 1, C subscript 2, alpha subscript g, and g (gelation conversion) are data-fitted coefficients.
Note: Use this model for thermoset materials that do not show yield behavior at low shear rates. For materials that do show yield behavior at low shear rates, use the Herschel-Bulkley-WLF viscosity model. For underfill encapsulants, use the viscosity model for Underfill Encapsulation.

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