Melt Flow Index (MFI) & Rheological Analysis
A masterbatch’s carrier resin must flow compatibly with the polymer on your production line. MFI is the primary way to measure this.
Flow compatibility determines blend quality.
The melt flow index (MFI / MFR) expresses, in grams, the amount of molten polymer that flows through a standard die in 10 minutes at a specified temperature and load (g/10 min). Its volumetric equivalent is the MVR (cm³/10 min).
The difference in flow between the masterbatch and the base polymer directly affects blend homogeneity, color distribution, and process stability. That is why carrier resin selection and MFI control are part of our quality process.
Rheological analyses help us understand the flow behavior of the melt under different conditions and guide formulation selection, especially on thin-film and high-speed lines.
Typical test conditions by polymer
| Polymer | Temperature | Load |
|---|---|---|
| PE | 190 °C | 2.16 kg |
| PP | 230 °C | 2.16 kg |
| PS | 200 °C | 5 kg |
| ABS | 220 °C | 10 kg |
For other polymers, the conditions of the relevant standard apply.
Benefits of MFI control
- Blend compatibility: the masterbatch disperses evenly in the melt
- Process stability: consistent flow from batch to batch
- Product quality: preventing surface defects and color fluctuations
How is it measured?
- Preparation
Conditioning
If required, the sample is dried and conditioned.
- Heating
Test temperature
The sample is brought to the test temperature in the cylinder.
- Flow
Standard load
The melt flows through the die under a standard weight.
- Calculation
MFI value
The cut samples are weighed and the flow rate is calculated in g/10 min.
Related pages
Let’s plan tests and samples for your product.
Share your application and target values; our laboratory will recommend the right product and prepare your sample along with its measurement results.
