rPET Is Now a Mainstream Requirement

Supermarket buyers increasingly specify recycled content in cups, trays and clamshells. That converts rPET from a sustainability story into a production planning question: where does the sheet come from, and can a thermoforming line run it reliably?

Shantou Longsheng Industry Co., Ltd. supplies the forming side of that chain — cup making machines, multi-station thermoforming machines and precision molds — and the sheet extrusion technology that feeds them.

The rPET Process Chain

1. Bale breaking and sorting — PET bottles are separated from caps, labels and foreign polymers
2. Washing and drying — hot wash removes glue and residue; moisture is the next enemy
3. Flake drying and crystallising — before melt processing, flake must be dried to very low moisture, exactly as virgin PET requires
4. Extrusion with melt filtration — screens catch remaining contaminants; degassing removes volatiles
5. Sheet calibration — three-roll polishing gives the gloss and thickness profile the forming step expects
6. Thermoforming — cups, trays and lids are formed and trimmed in the usual way

The drying and crystallising stage is decisive. The LSI series single screw sheet extruder from Longsheng includes this system, because hydrolysis during extrusion drops molecular weight and the resulting sheet becomes brittle — a defect no forming parameter can repair.

What Changes When Running rPET Instead of Virgin PET

• IV (intrinsic viscosity) varies batch to batch, so melt pressure and draw behaviour shift; process monitoring matters
• Colour and haze vary with flake source; many converters run a thin virgin skin layer over an rPET core to stabilise appearance
• Gel count is higher, so filtration and melt quality control carry more weight
• Food-contact status depends on the flake supplier's certification, not on the forming machine

What the Converter Can Expect From the Forming Side

rPET forms much like virgin PET: same temperature window, same clarity, slightly narrower process latitude. Longsheng cup machines (FS-8556, HSS-8556, HAI-8556) and multi-station thermoforming machines handle it with standard tooling practice.

Founded in 1998 in Shantou City, Guangdong Province, Longsheng operates a 30,000 square metre facility, holds 25 authorised patents and is a high-tech enterprise.

For rPET sheet projects, visit the official website: https://www.stlongsheng.com