Calcium Carbonate 

Product Overview

Calcium carbonate is one of the most widely used mineral fillers in composite, adhesive, and coating systems. Sourced from natural limestone and refined to various particle sizes, it serves as an inorganic bulk extender, contributing to both cost efficiency and functional performance in a range of resin systems.

Fine and medium grades of calcium carbonate are commonly used to adjust viscosity, enhance surface hardness, and improve dimensional stability of the final product — without compromising mechanical strength.

Key Benefits

• Cost-Effective Extender: Reduces resin consumption per unit volume, making it ideal for large-scale manufacturing and cost control.

• Rheology Modification: Improves thixotropic properties, sag resistance, and flow in gelcoats, adhesives, and putties.

• Enhanced Surface Properties: Increases scratch resistance and final product hardness; improves sanding characteristics.

• Thermal Stability: Offers excellent stability under processing conditions, with minimal reactivity.

• Resin Compatibility: Performs well in polyester, vinyl ester, epoxy, polyurethane, and acrylic systems.
  
  

Technical Specifications (Typical Ranges)

• Particle Size (D50):

  • Fine Grade: ~5–10 µm

  • Medium Grade: ~15–30 µm

• Purity: >96% CaCO₃ (natural)

• Moisture Content: <0.2%

• Oil Absorption: 15–25 g/100g (variable with grade)

• Bulk Density:

  • Fine: 0.8–1.1 g/cm³

  • Medium: 1.1–1.4 g/cm³

• pH (10% slurry): 8.5–9.5
  
  

Addition Rate

• General usage: 10%–50% by weight depending on the formulation

• Adhesives and Sealants: 10%–30%

• Putty and Fillers: 25%–50%

• Gelcoats and Coatings: 5%–15%

Proper dispersion is recommended using high-shear mixing for best performance and uniform distribution.

Applications

• FRP laminates, gelcoats, and putties

• Structural adhesives and sealants

• Industrial flooring and decorative coatings

• Thermal insulation boards and composite panels

• Casting compounds and filled epoxies