ISO/CD 306

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

General information

30.60   Close of voting/ comment period   Sep 8, 2026

ISO

ISO/TC 61/SC 2 Mechanical behavior

International Standard

Scope

This document specifies four methods for the determination of the Vicat softening temperature (VST) of thermoplastic materials:
—    Method A50 using a force of 10 N and a heating rate of 50 °C/h;
—    Method B50 using a force of 50 N and a heating rate of 50 °C/h;
—    Method A120 using a force of 10 N and a heating rate of 120 °C/h;
—    Method B120 using a force of 50 N and a heating rate of 120 °C/h.
The methods specified are applicable only to thermoplastics, for which they give a measure of the temperature at which the thermoplastics start to soften rapidly.

Life cycle

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PUBLISHED
ISO 306:2022

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IN_DEVELOPMENT
ISO/CD 306
30.60 Close of voting/ comment period
Sep 8, 2026