In the world of high-volume manufacturing, recycled plastic can be a dangerously vague term. If you are a production engineer or a procurement manager, you know that the success of your day depends on one thing: consistency.
When a batch of resin hits your extruder, it needs to behave exactly like the batch before it. At Polymer Processors, we ensure this through the science of the Melt Flow Index (MFI).
If you’ve ever wondered what our in-house experts are actually doing in the lab at 11 Japaddy Street, this is the deep dive for you.
What is MFI and Why Does It Matter?
At its simplest, the Melt Flow Index is a measure of how easily a plastic flows when it is melted.
We test this by heating a sample of our HDPE, LDPE, or PP pellets to a specific temperature and forcing it through a standardised tube using a precise weight.
The result—expressed in grams per 10 hours—tells us the viscosity of the plastic.
- High MFI: The plastic is runny when melted. This is ideal for Injection Moulding, where the plastic needs to flow quickly into complex, thin-walled moulds (like a nursery pot or a plastic crate).
- Low MFI: The plastic is thick or stiff when melted. This is essential for Film Blowing or Extrusion, where the plastic needs melt strength to hold its shape as it is stretched into a thin film or a heavy-duty pipe.
Why We Test Every Batch
Many backyard recyclers simply melt plastic and hope for the best. But under the leadership of John Wilson Jr., we’ve moved beyond guesswork.
Here is why our lab-tested MFI is a game-changer for your production line:
- Preventing Bubble Bursts in Film Blowing
If you are blowing LDPE film, an inconsistent MFI is your worst enemy. If the resin is too runny, the bubble will collapse or burst, leading to catastrophic downtime. By verifying the MFI, we ensure your film maintains its structural integrity from the start of the roll to the end.
- Optimising Machine Settings
Every time you have to adjust your heater bands or pressure settings to accommodate a bad batch of resin, you lose money. Our Technical Data Sheets (TDS) provide the exact MFI of your shipment, allowing your operators to set their machines with confidence and walk away.
- Maintaining Molecular Integrity
MFI isn’t just about flow; it’s a window into the health of the plastic. If the MFI is significantly higher than it should be, it can indicate that the plastic was overheated or cooked in a previous life, breaking down the polymer chains. Our lab ensures that the DNA of the plastic we provide is strong enough for industrial use.
Precision at Scale
With an annual capacity of 18,000 tonnes, we don’t have the luxury of being close enough.
Our state-of-the-art Italian Erma extruders and Sorema wash plants do the heavy lifting of purification, but it is our lab that provides the final green tick of technical authority.
As a 100% Australian-owned family business, we take pride in the fact that our pellets don’t just look like virgin material—they perform like it.
Don’t Let Your Production Line Become a Laboratory for Untested Resins
Talk to the team today to receive the latest specifications for our lab-verified HDPE, LDPE, and PP pellets. Let’s get the science right, so your machines never have to stop.