What is ISO 2921– Temperature-retraction procedure about?
ISO 2921 specifies a method for the determination of the temperature-retraction characteristics of stretched vulcanized rubber.
ISO 2921 does not cover thermoplastic rubbers, as many thermoplastic elastomers have a yield point in the range of 5 % to 20 % elongation.
Who is ISO 2921– Temperature-retraction procedure for?
ISO 2921 on adhesives is relevant to:
- Manufacturers of vulcanized rubber
- Chemical engineers
- Any entity responsible for testing and quality assurance of rubber and thermoplastic
Why should you use ISO 2921– Temperature-retraction procedure for?
A vulcanization process involves heating rubber with sulphur, accelerator and activator at 140–160°C.
ISO 2921 provides best practice guidance on methods and requirements for determining the low temperature characteristics for temperature retraction procedure test.
ISO 2921 specifies a method for stretching a piece of test piece at a standard laboratory temperature and then cooling it to a sufficiently low temperature to prevent retraction upon removal of the stretching force. The stretching force is then removed and the temperature is gradually increased.
Overall, ISO 2921 is a comprehensive guide to provide methods for determining the low temperature retraction characteristics, so users will gain a comprehensive understanding of the quality of vulcanized rubber to improve durability and strength.
What’s changed since the last update?
BS EN 2921:2019 supersedes BS EN 2921:2011, which is withdrawn and includes
- In 5.8, a clarification has been included as for how to set the slight tension on the test pieces.
- Precision results has been added as Annex B
