PET Bottle Flake Single Screw Pelletizing Line

Pelletizing transforms washed PET flakes into uniform, dense granules (typically 3–5 mm). This standardised form unlocks higher-value downstream reuse — including polyester fiber spinning, PET sheet extrusion, and injection molding — where flake feedstock would not be directly usable. Pellets also flow more reliably through downstream processing equipment and are easier to transport and store than flakes.

PET is highly hygroscopic. Even 300–500 ppm of residual moisture in the melt triggers hydrolytic chain scission — breaking the long polymer chains and dropping the intrinsic viscosity (IV). A lower IV means weaker mechanical properties and reduced suitability for demanding applications. This line addresses moisture on two fronts: the compactor provides initial pre-drying and densification, and the 2-zone vacuum degassing system pulls residual vapours from the melt, keeping the typical IV drop to ≤0.05 dL/g.

Yes. The melt filtration system can be configured with different screen fineness (40–150 µm) and filter change mechanisms to suit the contamination level of your input stream. Post-industrial or well-sorted post-consumer flakes may use a standard screen pack, while heavily contaminated streams benefit from a hydraulic auto screen-changer (back-flush type) to maintain output rate without production stops.

Post-consumer PET bottle flakes typically enter the line at IV 0.72–0.80 dL/g. With proper compaction, vacuum degassing, and controlled barrel temperatures, the output pellets typically retain an IV of 0.68–0.76 dL/g. This meets the specification for polyester fiber (0.40–0.65 dL/g) and is at or near the threshold for PET sheet and injection molding grades (0.70–0.85 dL/g). For bottle-to-bottle grade requiring IV >0.80 dL/g, a downstream Solid State Polymerization (SSP) stage would be required.

A single-screw extruder applies lower mechanical shear to the melt, which better preserves IV in standard PET bottle flake recycling. Twin-screw extruders offer superior distributive mixing and are preferred when compounding additives (chain extenders, colorants, fillers) into the melt — but their higher shear and complexity add cost and risk of greater IV degradation for straightforward flake-to-pellet recycling. Most post-consumer PET pelletizing plants use a single-screw configuration for this reason.

Yes. Remote commissioning guidance and operator training are available for all lines. All machines ship with a 1-year limited warranty covering manufacturing defects on key mechanical and electrical components. Spare parts and ongoing technical support are available beyond the warranty period. Contact us to discuss your installation requirements.