ISO 306:2022 - Plastics — Thermoplastic materials — Determination of Vicat softening temperature (VST)

ISO 306 specifies a standardized method for determining the Vicat softening temperature (VST) of thermoplastic materials. The VST is defined as the temperature at which a standardized needle penetrates a thermoplastic specimen under a specified load and heating rate, providing critical data on the material's heat resistance.

Scope:

• Testing Methodology: Describes procedures for applying a constant rate of temperature increase to a thermoplastic specimen until the needle penetrates to a specified depth.
• Measurement Parameters: Specifies different test conditions (A50, B50, A120, B120) based on the load applied (10 N or 50 N) and heating rate (50 °C/h or 120 °C/h).
• Material Applicability: Suitable for various thermoplastic materials to assess their softening behavior under heat.
• Environmental Testing: Allows testing under various environmental and operational conditions.

Applications:

• Material Selection: Aids in selecting thermoplastics for applications involving heat exposure.
• Quality Control: Ensures consistency in the heat resistance of thermoplastic products during manufacturing.
• Performance Testing: Evaluates a material's ability to maintain its shape and integrity under heat.
• Research and Development: Supports the development of thermoplastics with enhanced heat resistance.