ISO 1133: Plastics -- Determination of the melt mass-flow rate (MFR) and the melt volume-flow rate (MVR) of thermoplastics.

This standard specifies two procedures for the determination of the melt mass-flow rate (MFR) and the melt volume-flow rate (MVR) of thermoplastic materials under specified conditions of temperature and load. One is a mass-measurement method. The other is a displacement-measurement method. Normally, the test conditions for measurement of melt flow rate are specified in the material standard with a reference to ISO 1133. The test conditions normally used for thermoplastics are listed in annexes. 

The thermoplastics materials industry uses the Melt Flow Index (MFI) as a basic tool for quality control and acceptance of incoming products. The measure of the flow properties is contained on the identity card, and is used as a check to verify if the plastic's grade is within the required fluidity range. This is commonly used for polyolefins (polyethylene HDPE, LDPE, LLDPE, and polypropylene PP).

   

Common Melt Flow Rate Conditions by Material: