Measurement of Uniaxial Elongational Viscosity
for evaluating Blow Molding Processability



In the process of blow molding and vacuum molding, resin suffers elongational deformation. The measurement of viscosity (elongational viscosity) at the time of elongational deformation and its change (strain hardening property) provides information on molding processability and related information. The use of the rotating type rheometer makes it possible to measure uniaxial elongational viscosity at a given temperature and a given strain rate.

What can be made known

  • Uniaxial elongational viscosity value
  • Strain hardening property
  • Molding processability (example): If the material shows strain hardening property, it has good moldability.

Example of measurement

sample: PE having different branched chains

Measurement method

Testing conditions (our standard conditions)
Temp. range Strain rate range Specimen size (length x width x thickness)
25 ~ 250 ℃ 0.01 ~ 20 s-1 18 mm×10 mm×0.5 mm

Factors that affect viscosity (elongational viscosity) and its change (strain hardening property)

  • Existence/nonexistence of branched chains and the amount of branched chains
  • Existence of a high-molecular-weight component
  • Existence/nonexistence of a filler and the type of the filler

Search Number 6D007

Download The Technical Note of This Exapmle.

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