PETG shrink film is widely used for packaging applications requiring high clarity, excellent shrink performance, and strong sealability. To ensure consistent product quality, strict control measures are implemented throughout manufacturing.
Raw Material Inspection – Incoming PETG resin and additives are tested for intrinsic viscosity, moisture content, and contamination. Only certified materials with consistent melt flow index are approved for production.
Extrusion & Thickness Uniformity – During sheet extrusion, online gauging systems continuously monitor film thickness. Transverse direction (TD) thickness tolerance is kept within ±5%. Automatic profile control adjusts die bolts to maintain uniformity, as uneven thickness leads to poor shrink results.
Shrinkage Properties – Key parameters include free shrink ratio and shrink force. Samples are tested in hot water or an air oven at specified temperatures (typically 80–100°C). Acceptable TD shrinkage ranges from 60% to 80%, while machine direction (MD) shrinkage is kept below 5% to avoid distortion. Shrink force is measured with a tension meter to ensure adequate tightness without damaging products.
Optical & Mechanical Performance – Haze and clarity are measured using a haze meter; PETG film should achieve >90% clarity and <5% haze. Tensile strength (≥50 MPa in MD) and elongation at break are verified with a universal tester to guarantee handling durability.
Sealability & Anti-static Treatment – Heat seal strength and hot tack are evaluated on a sealer. Proper sealing window (e.g., 120–150°C) is confirmed. Static decay time is checked for anti-static grades.
Roll Appearance & Dimensions – Finished rolls are inspected for wrinkles, die lines, gel spots, and edge trimming. Roll width, core ID, and winding tension are recorded. Samples from each batch are retained for shelf-life monitoring.
All data is documented in a quality report. Non-conforming material is rejected or reworked. Regular calibrations of test equipment ensure measurement reliability. This comprehensive QC system guarantees that PETG shrink film meets customer specifications for high-speed packaging lines.
