High-purity calcium carbonate (HPCC) is one of the key mineral fillers in the coatings industry. It combines cost efficiency with improved hiding power, colour stability and application properties. Thanks to its chemical inertness and carefully controlled particle size distribution, HPCC helps optimize formulations across different market segments.
Key benefits of HPCC in paints and coatings
- HPCC enhances light scattering and partially replaces TiO₂ while maintaining the required level of whiteness.
- Fine particles (≤ 1 µm) increase hiding power and allow a reduction in the dosage of expensive TiO₂.
- Acts as an extender pigment, reducing overall formulation cost.
- In standard (economy/base) paints, TiO₂ replacement can reach 30–40%, and in premium grades – about 10–20%.
- Coarser fractions reduce viscosity and improve flow and levelling.
- Fine particles increase thixotropy and stabilize the suspension.
- Acid-treated grades provide better dispersion in solvent-borne systems.
- HPCC is chemically stable and does not degrade binders under UV exposure.
- Improves abrasion resistance and overall wear resistance of the coating.
- Fine particles enhance film strength and wet scrub resistance.
- Fine fractions (1–2 µm) promote the formation of glossy coatings.
- Coarser fractions (5–10 µm) provide matte or semi-matte effects.
- The effect becomes pronounced at higher filler levels (>15–20%).
- Helps maintain a mildly alkaline pH range (around 9), ensuring the stability of waterborne paints.
- In acidic systems (pH < 6), HPCC may dissolve with CO₂ release, therefore it is mainly used in neutral and alkaline formulations.
- HPCC is a natural, inert mineral that does not emit VOCs.
- Using HPCC reduces the carbon footprint compared to synthetic fillers.
- Safe for humans and the environment.
Particle size distribution: The particle size distribution of calcium carbonate is a critical factor influencing its performance in paints and coatings. Fine particles (typically less than 1 micron) are preferred for applications requiring high opacity and smooth surface finish. Coarser particles (up to 10 microns) are used in applications where cost reduction and improved mechanical properties are prioritized. The optimal particle size distribution ensures uniform dispersion within the paint matrix, enhancing the overall properties of the coating.
Surface treatment types: Surface treatment of calcium carbonate is essential to improve its compatibility with paint resins. Common treatments include stearic acid coating, which enhances the hydrophobicity of calcium carbonate, improving its dispersion in non-polar systems. Silane coupling agents are also used to enhance the bonding between calcium carbonate and the paint matrix, resulting in improved mechanical properties and durability. Proper surface treatment ensures better adhesion, reduced moisture absorption, and enhanced processing stability.
Application areas of HPCC
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Enhanced opacity & whiteness: Ensures superior coverage with fewer layers.
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Durability & color retention: Protects surfaces from fading and degradation.
- Decorative coatings: provide brightness and uniformity of the final film.
- Industrial and protective coatings: enhance abrasion resistance and weatherability.
- Powder coatings: contribute to uniform deposition and cost-efficient formulations.
Cemix offers high-purity calcium carbonate with an optimized particle size distribution, high chemical stability and consistent quality. Its use allows formulators to:
- increase coating durability,
- reduce costs without compromising quality,
- improve rheology,
- develop formulations that meet modern environmental standards.
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Improved Flow & Dispersion: Enhances application uniformity.
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Cost Efficiency: Reduces reliance on expensive additives.
At Cemix, we offer high-purity GCC grades tailored to optimize performance in paints and coatings. Our precisely engineered products provide consistent particle size distribution, chemical stability, and excellent opacity enhancement. By incorporating Cemix GCC into your formulations, you achieve better durability, optimized rheology, and reduced costs, ensuring coatings that meet the highest industry standards.