Principle

Vicat softening temperature

Vicat Softening Temperature (VST)

The “Vicat Softening Temperature (VST)” can be defined as the temperature against which a flattened needle with a tip of 1 mm² penetrates 1 mm into the surface of a specified sample.

Testing procedure

A flat sample with a minimal surface of 10 x 10 mm and a thickness between 3 and 6 mm is placed into the tester:

A load of 10 or 50 N is applied to the sample. This setup is placed into an oil bath which is heated at a speed of 50 of 120 °C/h till the needle penetrates 1 mm into the material.

Testing applications

  • Determination of the softening temperature of a material
  • Comparison of the temperature resistance of materials

ISO 306:2013

Plastics -- Thermoplastic materials -- Determination of Vicat softening temperature (VST)