At above roughly one tonne per hour of throughput, the co-rotating twin-screw extruder has become the consensus platform for plastics recycling, four leading machinery builders said, with screw profiles on a medium-sized machine now reconfigurable in one to two hours.

That threshold is where the technology pulls ahead decisively of single-screw systems, Coperion General Manager Peter von Hoffmann said. Below it, single-screw delivers adequate quality. Above it, twin-screw offers demonstrably better homogenisation, degassing and melt stability without generating gels.

What does the modular approach actually deliver?

Low-bulk-density post-consumer film — shredded material that traps large volumes of air — ranks as the most-cited engineering headache across EREMA, Coperion, ICMA San Giorgio and Starlinger.

Coperion's MegaFeed unit, a side feeder with a conical twin-screw and a wide opening, targets this problem directly. "Once it is in the machine, you are melting it anyway and the density climbs," Hoffmann noted. "But getting it in is the important thing."

ICMA San Giorgio's Giorgio Colombo said the company's ONE-STEP UP-CYCLING concept feeds lightweight flakes directly into the twin-screw, bypassing upstream agglomeration. The approach avoids an extra thermal cycle, though Colombo acknowledged that high-performance compounding — fillers, virgin polymer blends — still requires a second downstream extruder in a cascade configuration.

EREMA's response sits on three engineering levers:

• EcoGentle, for stable plasticising across varying viscosities
• VOLEX, for high-performance degassing and VOC reduction at full throughput
• ReFresher, for downstream odour management

Starlinger's Paul Niedl said the builder's PCUplus pellet conditioning unit strips residual odour at line end, opening sensitive applications including cosmetics packaging.

Why has twin-screw won the consensus vote?

The co-rotating configuration holds three practical advantages over single-screw:

• Modular screw elements that processors can physically reconfigure
• Screw change on a medium machine completed in one to two hours
• Above 1 t/h, better homogenisation and degassing without gels

Hoffmann tied the technology's consolidation to the period after China closed its borders to imported plastic waste, when domestic European processors had to handle much larger streams at scale.

ICMA's Colombo drew the operating line clearly: "Flexibility must be engineered, not assumed."

What does food-grade PET actually require?

EFSA and FDA approval set the regulatory floor, requiring challenge testing that proves contaminant removal to concentrations well below permitted limits. Starlinger's recoSTAR PET systems restore intrinsic viscosity critical to bottle-to-bottle mechanical performance.

Hoffmann disputed the assumption that food-grade capability demands a fundamentally different or costlier extruder. The same twin-screw architecture — fitted with appropriate vacuum degassing and process control — covers both food-contact and standard industrial runs.

Niedl identified a harder commercial constraint: brand-owner specifications. Major consumer-goods buyers set recycled-content thresholds that often exceed EFSA and FDA requirements. "The plastics industry never stands still," he said. "Our technology also needs to keep evolving to meet higher contamination levels on the one hand, and increased quality requirements for recycled content on the other."

What's different about chemical recycling feedstock prep?

Pyrolysis feedstock preparation flips the thermal logic of mechanical recycling. Where mechanical lines push melt temperatures down, chemical lines push them up — feeding a continuous melt at temperatures approaching 350 degrees Celsius into the downstream reactor.

The scale jump is sharp:

• Mechanical line: ~1 tonne per hour on a 70-millimetre screw
• Chemical feed prep: ~6 tonnes per hour from a 133-millimetre machine

EREMA's CHEMAREMA design handles variable upstream input properties ahead of the pyrolysis reactor. Coperion runs pilot chemical recycling lines in Europe. Hoffmann described the sector as gaining "firsthand experience" of how much of the waste problem pyrolysis can realistically address.

Where does the industry head from 2026?

The four executives converged on a paradoxical forecast: simultaneous movement toward greater specialisation and greater flexibility. EREMA's Markus Huber-Lindinger, the company's Managing Director, coined the framing: "specialisation at the edges, flexibility in the core." Colombo argued flexibility will dominate as feedstock variability grows. Hoffmann pointed to plant-scale integration — turnkey wash-line-plus-compounding systems that take raw waste to a market-ready pellet in one integrated footprint.

Huber-Lindinger is direct about the underlying constraint: when processors ask for one line that runs everything, they typically compromise on throughput, quality or operating cost. Versatility is possible, he said, but physics sets boundaries.

The unresolved milestone for buyers is regulatory and commercial at once. As EFSA updates challenge-test protocols and brand owners tighten recycled-content specifications through 2026 and 2027, processors will determine whether to commit capital to modular platforms or to dedicated single-stream lines.