| 1 | Filler Loading Confirm the mineral content stated on the technical data sheet. | Calcium carbonate content: 70–85 wt% for many high-loading PE filler masterbatch grades. | Select the loading according to the target cost, stiffness, opacity, and final-product requirements. | Use thermogravimetric analysis or an appropriate ash-content method. Check several samples from different production lots. | Higher loading can reduce resin consumption, but excessive filler may lower elongation, impact strength, and process stability. |
| 2 | Filler Dispersion Look for uniform distribution without visible agglomerates. | Microscopy should show a consistent particle distribution with no large clusters; a practical internal limit is often 50–100 μm for visible agglomerates. | Aim for a uniform dispersion grade suitable for the film, sheet, injection-molding, or extrusion application. | Prepare a thin molded or extruded section and inspect it by optical microscopy at approximately 100–200× magnification. | Poor dispersion can cause streaks, weak spots, die build-up, surface defects, and unstable mechanical properties. |
| 3 | Particle Size and Distribution Evaluate the mineral particle size and the presence of oversized particles. | Fine calcium carbonate grades commonly use a median particle size around 1.5–5 μm, depending on the application. | Film applications generally require finer and more consistent particles than some thick-wall molded products. | Request laser-diffraction particle-size data, including D50 and the coarse-particle fraction. ISO 13320 is commonly used for laser diffraction analysis. | Smaller, well-controlled particles generally support smoother surfaces and more consistent dispersion, but may increase formulation cost. |
| 4 | Melt Flow and Processing Behavior Match the masterbatch flow characteristics with the host PE resin. | Melt mass-flow rate may commonly fall within approximately 5–15 g/10 min, but the test temperature and load must be specified. | The masterbatch should feed smoothly and should not cause excessive pressure fluctuation, torque increase, or output loss. | Compare melt mass-flow rate using the same test condition for all samples, such as ASTM D1238 conditions appropriate for the selected PE grade. | A major mismatch in flow can lead to poor dosing, uneven filler distribution, unstable extrusion, and inconsistent product thickness. |
| 5 | Moisture and Volatile Content Check whether the product can be processed without drying-related defects. | A commonly requested moisture target is ≤0.20 wt%; lower limits may be preferred for thin film and high-speed extrusion. | Use a tighter moisture specification when processing at high output or when surface appearance is critical. | Test moisture by a calibrated moisture analyzer or an appropriate loss-on-drying method. Store samples in sealed packaging before testing. | Excess moisture may contribute to bubbles, pinholes, silver streaks, surface roughness, and inconsistent extrusion pressure. |
| 6 | Carrier Resin Compatibility Ensure the carrier is compatible with the host PE and the production process. | Identify whether the carrier is LDPE, LLDPE, HDPE, or another compatible polyolefin, and confirm the recommended let-down ratio. | A starting trial level of 10–30% masterbatch is common, but the final dosage depends on the required filler level and product performance. | Run a controlled trial at the intended dosage and compare torque, melt pressure, surface appearance, tensile properties, and seal performance where applicable. | Good carrier compatibility improves feeding, mixing, mechanical performance, and the consistency of the final PE compound. |
| 7 | Thermal Stability and End-Use Performance Evaluate performance under the actual processing and application conditions. | Typical PE processing zones may operate around 170–220°C, depending on resin type, equipment, residence time, and product design. | The masterbatch should process without abnormal odor, discoloration, gas formation, severe die build-up, or unacceptable property loss. | Conduct a pilot trial using representative barrel temperatures, screw speed, residence time, and cooling conditions. Test tensile strength, elongation, impact, opacity, or stiffness as required. | Laboratory data alone may not reveal process-specific defects; production-like trials confirm whether the masterbatch meets real operating requirements. |