Over deze norm
This International Standard specifies the methods for the determination of the melt mass-flow rate (MFR) and the melt volumeflow rate (MVR) of thermoplastic materials under specified conditions of temperature and load. Normally, the test conditions for measurement of melt flow rate are specified in the material standard with a reference to this International Standard. The test conditions normally used for thermoplastics are listed in annexes A and B. The MVR will be found particularly useful when comparing filled and unfilled thermoplastics. The MFR can now be determined from automated MVR measurements provided the melt density at the test temperature and pressure is known. These methods are in principle also applicable to thermoplastics for which the rheological behaviour is affected to a limited extent during the measurement by phenomena such as, hydrolysis, condensation, or cross-linking, but only if the repeatability and reproducibility are within the expected range and acceptable for these test methods. For materials which show significantly affected rheological behaviour during testing which cannot be stabilized, this test is not appropriate. In these cases, the use of viscosity number in dilute solution according to ISO 1628 is recommended for characterisation. The rates of shear in these tests are much smaller than those used under normal conditions of fabrication, and therefore data obtained by these methods for various thermoplastics may not always correlate with their behaviour in actual use. Both methods are useful in quality control.