ISO 13145 describes a method for determining the viscosity and stress relaxation of raw or compounded rubber under specified conditions, using a rotorless sealed shear rheometer.
The viscosity determination is a test at constant strain, temperature and frequency, from which the elastic and loss components of the complex shear modulus can be determined. The stress relaxation determination is a test at constant static strain and temperature, in which the decrease in torque is recorded. Rubber labs use the two measurements to characterize raw polymers and compounds for processing, and report the test conditions with the results so batches can be compared.
Both measurements are made on a rotorless sealed shear rheometer. Our RPA Ultra rubber process analyzer supports viscosity and stress relaxation testing to ISO 13145. If you need help matching ISO 13145 requirements to your parts or setup, contact our team.
