Recycling: New Ultra-Fine Melt Filtration for PET Recycling

Ettlinger Kunststoffmaschinen GmbH of Germany (U.S. office in Tyrone, Ga.) has unveiled its latest ECO series melt filters with a smaller filtration screen of 60 µm. This reportedly will make it easier to treat recycled material for extruding post-consumer PET bottle flake and fines into sheet, packaging tape and fiber and help plastics recyclers remove challenging contaminants like paints, silicones, barrier materials, crosslinked fractions and gels from the melt.

The purity of the recycled material is central to its usability. Ettlinger says that in the PET world, the efficiency of the melt filtration process is far more critical than usual on the recycled material production line. The screen changers and screens normally employed for this purpose have limitations here, whereas Ettlinger’s self-cleaning ECO filter systems permit compliance with even the toughest specifications.

The core component of the ECO filter is a rotating, cylindrical steel screen with millions of laser-drilled, conical holes. When melt flows through this screen from the outside to the inside, any contaminants are retained on the surface and continuously removed by a scraper. The launch of a microperforation with a filtration fineness of 60 µm is described by the company as a “decisive breakthrough” for PET recycling.

The company says its continuous melt filters regularly open up new possibilities for materials that have traditionally been considered too heavily contaminated or that contain extremely problematic contaminants. Ettlinger’s rigid filter screen with laser-drilled microperforation is said to yield much better separation efficiency than standard woven steel-mesh screens.. Due to the new 60 µm filtration fineness, the few residual contaminants are no longer visible to the human eye. Significantly reduced occurrence of black specks and other particles helps make the downstream processing more efficient because contaminants results in virtually no torn tapes or fibers.