China – Food Grade HDPE Milk Flakes Recycling Machine
About Project:
- Location: China
- Material: Post-industrial & Post-consumer HDPE milk bottles (pre-washed flakes)
- Machine Model: SJ110+TSSK75
- Main Objective:To transform highly contaminated milk bottle waste into clean, dry flakes suitable for high-quality pelletizing.
Challenge:
Recycling HDPE milk bottles (typically white or translucent) requires much higher standards than general industrial plastic recycling. Faced several technical hurdles:
- Odor Removal: Residual milk proteins can create a sour odor if not properly degassed during extrusion.
- Color Purity: Any carbonization or “black spots” would ruin the value of the recycled HDPE, which must remain snow-white or ivory.
- Physical Properties: The recycled pellets needed to maintain a specific Melt Flow Index (MFI) to be used again in blow-molding new containers or high-end chemical bottles.
Purui Customized Granulating Solution:
Purui Machinery engineered a high-specification double-stage granulating system to meet these food-grade requirements:
- Forced Side-Feeding System: Since milk flakes are often lightweight and irregular, we implemented a stable side-feeder. This prevents material bridging and ensures a constant, high-pressure flow into the primary extruder.
- Gentle Screw Geometry: We designed a specialized screw with a low-shear profile. This prevents the “over-cooking” of the HDPE, preserving the polymer chain length and maintaining the bright white color without yellowing.
- Two-Stage Ultra-Fine Filtration: The first stage removes bulk impurities, while the second stage uses a high-precision hydraulic screen changer to filter out particles as small as 80–100μm, ensuring the surface of the blown bottles is perfectly smooth.
Results & Performance:
- Odor-Free Output: The pellets passed the sensory test for residual odors, making them suitable for high-end secondary packaging.
- Zero Black Spots: The optimized flow path in the die-head eliminated “dead zones” where plastic could burn.
- High ROI: The client successfully replaced 30% of their virgin HDPE resin with these recycled flakes, significantly lowering production costs while hitting sustainability targets.
Why the Client Chose Purui Machinery?
“In the food-packaging sector, there is zero room for contamination. Purui’s plastic recycling granulation machine gave us the degassing power we couldn’t find in standard machines. Their local service team in China provided seamless installation and staff training.” – Technical Director, Food Packaging Group.