The ISO equivalent of ASTM D1238 for determining the Melt Flow Index (MFI) or Melt Flow Rate (MFR) of thermoplastic materials is ISO 1133. ISO 1133 is the international standard developed by the International Organization for Standardization (ISO) that provides guidelines for conducting MFI tests.
ISO 1133 and ASTM D1238 have similar objectives and principles, aiming to measure the melt flow properties of thermoplastic materials. Both standards specify the test conditions, such as temperature, load, and test methods, to ensure consistent and comparable results across different laboratories and testing facilities.
While there may be slight differences in specific test parameters and terminology between the two standards, ISO 1133 can be considered the ISO equivalent of ASTM D1238. Manufacturers and testing laboratories often choose the relevant standard based on regional requirements, industry specifications, or customer preferences.