rPET & Polyester: Intrinsic Viscosity, Packaging, Closures and Fibers
One polymer, several markets, and a chemistry that helps in sheet and hurts in fiber. The rPET guides, and the two distinctions worth keeping straight.
PET is one polymer with several quite different markets: bottles, sheet for trays and cups, strapping, and fiber, which is the largest of them. Recycled PET behaves differently in each, and the additive chemistry that helps one can hurt another. This hub collects what we have written about that.
The guides
- GUIDErPET packaging4 minThe two gates recycled PET has to pass: food law and physics.
- GUIDErPET thermoforming5 minWhy recycled sheet sags in the oven, and what the additive is claimed to do.
- GUIDErPET fibers and filaments3 minThe least forgiving process, and why it needs a linear chemistry rather than a branching one.
- GUIDEChoosing an rPET masterbatch3 minThe questions that separate suppliers, when the marketing copy does not.
The two things to keep separate
Food contact and performance are different questions with different authorities. Regulation (EU) 2022/1616 governs whether recycled plastic may touch food, by authorising recycling technologies and processes. Nothing in it says the material will run on your line. The recycled content minimums say how much you must use; they do not say it will work either.
Branching and linear chain extension are the second pair to keep apart. Branching builds melt strength, which a sheet needs to hold its shape. In spinning, the same branching broadens the molecular weight distribution and makes drawing uneven. Nexam Chemical sells separate grades for the two cases, which is the clearest public signal of what its chemistry does.