Polymers and coatings
Calcium carbonate for plastics.
A natural aragonite ground calcium carbonate for compounders, supplied as PL-CAL to the particle specification the formulation calls for.
The filler role
The formulation sees the delivered powder, not the mineral name.
Calcium carbonate is among the most widely used mineral fillers in polymer compounding. What it does in any particular formulation — stiffness, opacity, surface finish, rheology, cost per unit volume — depends on the matrix, the loading, the particle profile and the processing, which is why a filler is qualified in the formulation rather than on a data sheet.
- Composition
- 96.17% CaCO3
- Surface area
- > 1.7 m2/g
- Specific gravity
- 2.93
- PL-CAL sizing
- To specification
Representative analysis, ASTM C 25, Bowser-Morner report 124914A.
Keck Lab, representative analysis.
Material density, for volume-loading and let-down calculations.
Ground and classified to the product target across mesh 20 to 325.
What a compounder specifies
Four specifications decide the powder.
Particle-size targets
Define D10, D50, D90, top size, residue and agglomerate limits from the formulation and process requirement. Particle profile is what governs dispersion, viscosity and surface finish.
Moisture and handling
Set limits for moisture, bulk handling, feeding, dust collection and storage against the production system the powder has to run through.
Surface and compatibility
State whether the formulation requires an untreated or a surface-treated product, along with resin or binder compatibility, dispersion energy and additive interactions.
Finished-property testing
Measure rheology, mechanical properties, opacity, gloss, surface finish and weathering as applicable, against the incumbent filler under the same processing conditions.
How performance gets established
In the matrix, not on a data sheet.
Mineral identity is a starting point, not a result. Aragonite and calcite are calcium-carbonate polymorphs with different crystal systems. That difference is real, and what it produces in a filled polymer still has to be established in the actual matrix.
Loading and dispersion are trial outcomes. The workable loading, the dispersion energy required and the property trade-offs come out of controlled laboratory or pilot batches run against the incumbent filler on the same equipment.
Compare like with like. Run the candidate and the incumbent under identical processing conditions and measure the properties the finished part is actually specified on.
Material comparison
Aragonite GCC, calcitic GCC and precipitated carbonate.
| Decision factor | Aragonite GCC | Calcitic GCC | Precipitated CaCO3 |
|---|---|---|---|
| Origin and form | Natural orthorhombic CaCO3, marine deposit | Natural calcitic CaCO3, quarried | Manufactured calcium carbonate |
| Particle profile | Ground and classified to the product target | Ground and classified to the product target | Process-designed; grade-specific |
| Surface area | > 1.7 m2/g representative | Grade-dependent | Grade-dependent |
| Density (g/cm3) | 2.93 | 2.71 for calcite | Grade- and process-dependent |
| Substitution decision | Formulation and process testing | Formulation and process testing | Formulation and process testing |
Evaluation path
From particle target to production line.
Set the target
Provide the matrix, intended loading, particle specification, appearance targets and process constraints.
Compound
Run controlled laboratory or pilot batches against the incumbent filler using the same processing conditions.
Produce
Transfer the selected particle profile and processing conditions into the manufacturing plan.
Questions
Frequently asked questions.
What does calcium carbonate do in a plastic?
It is a mineral filler, one of the most widely used in polymer compounding. Its effect in a given formulation — on stiffness, opacity, surface finish, rheology and cost per unit volume — depends on the matrix, loading, particle profile and processing, so it is qualified by compounding trials rather than from a specification alone.
Is aragonite GCC different from calcitic GCC?
Both are natural ground calcium carbonate, but they are different mineral polymorphs: aragonite is orthorhombic at 2.93 g/cm3, calcite is trigonal at 2.71 g/cm3. The oolitic morphology also starts from rounded grains rather than angular quarried rock. What that produces in a filled system is established in the matrix.
What particle sizes are available?
PL-CAL is ground and classified to the product target, with sizing across mesh 20 to 325 depending on the application. Send the D10, D50, D90, top-size and residue targets your formulation runs to and the grade is matched against them.
Is the product surface treated?
State the requirement with the enquiry. Untreated and surface-treated needs, resin or binder compatibility, dispersion energy and additive interactions are part of the product specification discussed at the outset rather than assumed.
What loading should I use?
That is a trial outcome. Workable loading depends on the polymer, the particle profile, the processing equipment and the properties the finished part is specified on. Run controlled batches against the incumbent filler under the same conditions.
What documentation is available?
Grade specifications, particle-size data, analytical documentation and the safety data sheet, available through the contact form. The plastics industry brochure and the master technical data sheet are in the resources library.
Keep reading
Where to go next.
Discuss a particle target and formulation program.
Send the matrix, intended loading, target distribution, annual volume and destination, and AragoCor will match a grade and quote against it.