CaCO₃ Loading: 70% vs 75% vs 80% — Which Grade Is Right for Your Application?
A technical comparison of high-loading filler grades — covering mechanical property trade-offs, processing considerations, and application fit.
Blau Batch FMPE and FMPP series are available in three CaCO₃ loading levels: 70%, 75%, and 80%. Higher loading means more filler per kilogram of masterbatch — which translates to greater cost savings per tonne of finished product, but also different processing behaviour and mechanical property profiles. This guide helps you select the right grade for your application.
What Loading Level Means in Practice
CaCO₃ loading refers to the weight percentage of calcium carbonate in the masterbatch. An 80% loading means 800g of CaCO₃ per kilogram of masterbatch — a very high concentration. At the same let-down ratio, an 80% grade delivers significantly more filler into the finished part than a 70% grade, resulting in higher potential savings but also a denser mineral matrix.
| Grade | CaCO₃ Content | Polymer Carrier | Best For | Max Recommended Dosage |
|---|---|---|---|---|
| FMPE-1070 / FMPP-1070 | 70% | PE / PP | Applications requiring good elongation and tear resistance | 25–30% |
| FMPE-1075 / FMPP-1075 | 75% | PE / PP | Balanced cost savings and mechanical properties | 20–25% |
| FMPE-1080 / FMPP-1080 | 80% | PE / PP | Maximum cost reduction; rigid or low-specification applications | 15–20% |
Mechanical Property Trade-Offs
As CaCO₃ loading increases, the masterbatch becomes more mineral-dense. At the same let-down ratio, higher-loading grades introduce more filler into the polymer matrix, which typically: increases stiffness (tensile modulus), reduces elongation at break, reduces tear strength in film applications, and may slightly reduce impact resistance.
For blown film applications with tight elongation specifications, we generally recommend starting with the 70–75% grade. For rigid injection-moulded parts, bags, or low-cost commodity applications where elongation is not critical, the 80% grade often delivers the best economics.
Processing Considerations
Higher-loading grades are inherently more viscous and may increase back pressure on your extruder. At very high dosage rates (20%+), ensure your screw design can handle the increased filler load without excessive wear. Melt temperature profiles may need adjustment — our TDS sheets include grade-specific processing recommendations.
Which Grade Should You Start With?
If you are new to filler masterbatch: start with FMPE-1075 or FMPP-1075 at 15–20% dosage. This mid-range grade gives you meaningful cost savings while maintaining a processing window close to your existing parameters. Once you are comfortable with the behaviour, you can assess whether moving to a higher-loading grade makes sense for your application.
Contact our technical team with your existing polymer spec and application, and we will recommend the appropriate starting grade and dosage for your first trial.
Our technical team can recommend the right grade and dosage for your specific production requirements — usually within 24 hours.