| 1 | Confirm Pigment Quality | Pigment type, lightfastness, heat resistance, and chemical stability | The pigment should remain stable during PE processing, storage, and intended end use without significant fading, bleeding, or migration. | Request a technical data sheet with pigment classification, heat-resistance rating, lightfastness rating, and recommended processing temperature. | Review documentation and test molded plaques under actual processing conditions. |
| 2 | Measure Color Strength | Tinting strength and dosage efficiency | Higher color strength can reduce masterbatch addition rates, material cost, and the potential effect on mechanical properties. | Compare samples at the same let-down ratio, resin type, melt temperature, and molding conditions. Set an internal color-strength tolerance, such as ±5% from the approved standard. | Use spectrophotometer readings and molded plaque comparisons. |
| 3 | Check Dispersion Quality | Pigment particle distribution and absence of agglomerates | Well-dispersed pigment helps prevent streaks, specks, color variation, filter blockage, and weak points in the finished PE product. | The extrudate or molded surface should be free from visible pigment clusters and streaks at the intended dosage. | Run a film, sheet, or plaque trial and inspect it under consistent lighting and magnification. |
| 4 | Evaluate Color Consistency | Batch-to-batch repeatability and shade accuracy | Consistent masterbatch should produce the same shade when tested at the same addition rate and processing conditions. | Establish a color difference limit, commonly expressed as ΔE, according to the product’s visual requirements; tighter limits are needed for premium appearance parts. | Compare retained samples from multiple lots using an appropriate spectrophotometer and approved reference plaque. |
| 5 | Verify PE Compatibility | Carrier resin compatibility with HDPE, LDPE, LLDPE, or other PE grades | A compatible carrier promotes uniform mixing and reduces the risk of surface defects, poor mechanical performance, or processing instability. | The carrier should match the application’s PE family and processing method, including film extrusion, blow molding, injection molding, or extrusion coating. | Conduct a trial using the actual PE grade and compare melt behavior, surface appearance, and mechanical properties. |
| 6 | Review Processing Performance | Melt flow, thermal stability, moisture, and filtration behavior | Stable processing should not cause excessive pressure fluctuation, die build-up, odor, smoke, or degradation at the specified temperature. | Melt flow rate should be suitable for the target process, while moisture and contamination should remain within the supplier’s documented limits. | Check the certificate of analysis and record pressure, torque, temperature, output, and visible defects during a production-representative trial. |
| 7 | Assess Compliance and Supply Reliability | Regulatory documentation, traceability, packaging, and delivery consistency | Reliable documentation and lot traceability support quality control and help meet application-specific regulatory requirements. | Obtain SDS, technical data sheet, certificate of analysis, lot number, recommended storage conditions, and applicable regulatory declarations. | Audit sample records, packaging integrity, shelf-life information, and delivery lead-time performance before approval. |