Polymers and coatings
Calcium carbonate for plastics.
Natural oolitic aragonite for compounders: a screened and classified marine calcium carbonate, supplied untreated 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
What that depends on
- The matrix
- The loading
- The particle profile
- The processing
That is why a filler is qualified in the formulation rather than on a data sheet.
- Composition
- 96.17% CaCO3Representative analysis, ASTM C 25, Bowser-Morner report 124914A.
- Surface area
- > 1.7 m2/gKeck Lab, representative analysis.
- Specific gravity
- 2.93Representative analysis; material density, for volume-loading and let-down calculations.
- PL-CAL sizing
- To specificationClassified to the customer’s specification, within the custom classification range of 20–325 U.S. mesh; no published size band.
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
PL-CAL is supplied untreated. If the formulation runs a surface-treated filler, that treatment is a separate downstream step and not part of AragoCor supply. Set resin or binder compatibility, dispersion energy and additive interactions on that basis.
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
Oolitic aragonite, calcitic GCC and precipitated carbonate.
| Decision factor | Oolitic aragonite (PL-CAL) | Calcitic GCC | Precipitated CaCO3 |
|---|---|---|---|
| Origin and form | Natural orthorhombic CaCO3, marine deposit | Natural calcitic CaCO3, quarried | Manufactured calcium carbonate |
| Processing | Natural grains washed, screened, dried and classified; no grinding step in the published process | Quarried rock, ground and classified to the product target | Precipitated; process-designed and grade-specific |
| Surface treatment | Supplied untreated | Untreated or treated, by product | Untreated or treated, by product |
| 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 |
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.
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 PL-CAL a ground calcium carbonate (GCC)?
Not in the usual sense. GCC is quarried limestone or marble that is ground to a target distribution. PL-CAL is natural oolitic aragonite: marine grains that are washed, screened, dried and classified, and the process description PDS-OA-001, available on request, contains no grinding step.
It is offered to compounders as an alternative to calcitic GCC fillers. If a custom particle target would need milling, whether that is available and who performs it is confirmed on inquiry.
The two are also different mineral polymorphs: aragonite is orthorhombic at 2.93 g/cm3, calcite is trigonal at 2.71 g/cm3, and the oolitic grains start rounded rather than as angular crushed rock. What that produces in a filled system is established in the matrix.
What particle sizes are available?
PL-CAL is classified to the customer’s specification, within the custom classification range of 20–325 U.S. mesh; it has no published size band. 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?
No. PL-CAL is supplied untreated: processing is mechanical only, with no chemical treatment and no additives at any stage, according to the process description PDS-OA-001. If your formulation runs a surface-treated filler, treatment is a separate downstream step, so compare untreated PL-CAL with an untreated incumbent, or treat both the same way before comparing.
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 PL-CAL grade sheet and the master technical data sheet are in the resources library.
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.