Coated vs. Uncoated Calcium Carbonate: Which One Should You Choose?
Compare coated and uncoated calcium carbonate: surface treatment with stearic acid, advantages in plastic and rubber applications, and how to choose the right type. Tan Ky Mineral – ISO 9001:2015 certified CaCO₃ manufacturer. Contact us for a quotation and product catalogue!
1. Overview of Calcium Carbonate (CaCO₃)
Calcium Carbonate (CaCO₃) is one of the most widely used minerals in industrial production. Found naturally in limestone and marble, it offers high brightness, purity, and cost-effectiveness—making it a preferred filler in plastic, rubber, paint, paper, and construction materials.
In the plastic and rubber industries, CaCO₃ acts as a filler additive that helps:
Reduce production costs,
Improve mechanical strength and stability,
Enhance product whiteness and surface finish.
Depending on the processing requirements, manufacturers can use Coated CaCO₃ (surface-treated with stearic acid) or Uncoated CaCO₃ (untreated). Let’s explore their differences and applications in detail.
2. Coated vs. Uncoated Calcium Carbonate: Key Differences
| Criteria | Uncoated CaCO₃ | Coated CaCO₃ (Stearic Acid Treated) |
|---|---|---|
| Particle surface | Rough, hydrophilic | Smooth, hydrophobic |
| Dispersion in polymers | Poor | Excellent |
| Mechanical enhancement | Moderate | High |
| Moisture absorption | High | Low |
| Typical applications | Paint, paper, construction materials | Plastic, rubber, masterbatch |
| Cost | Lower | Slightly higher |
💡 Core difference:
The stearic acid coating modifies the particle surface from hydrophilic to hydrophobic, allowing better compatibility with polymer matrices (PP, PE, PVC, etc.). This results in enhanced dispersion, durability, and finish quality.
3. The Stearic Acid Coating Process
Tan Ky Mineral’s CaCO₃ coating process diagram
At Tan Ky Mineral, the surface treatment process is performed with modern technology, ensuring uniform coating and consistent quality.
Main steps:
- Heating CaCO₃ particles to approximately 120°C.
- Spraying purified stearic acid into a high-speed mixing chamber.
- Intensive blending to ensure even coverage of each CaCO₃ particle.
- Drying and packaging for shipment.
👉 Coated CaCO₃ particles with a smooth, hydrophobic surface that disperse perfectly in plastic and rubber compounds—delivering superior strength, gloss, and stability.
4. Advantages of Coated CaCO₃ in Plastic and Rubber Industries
4.1. In Plastic Applications
Improved dispersion: eliminates agglomeration and uneven mixing.
Enhanced surface gloss and transparency.
Cost reduction: replaces 20–40% of virgin resin without compromising performance.
Better mechanical properties: increases tensile strength, impact resistance, and dimensional stability.
4.2. In Rubber Applications
Improved curing and elasticity.
Higher wear resistance and tensile strength.
Better mixing efficiency, reducing milling time.
More stable product performance under stress and temperature changes.
5. When to Use Coated or Uncoated CaCO₃
| Application | Recommended Type |
|---|---|
| Masterbatch, PE/PP film, PVC pipe, plastic components | Coated CaCO₃ |
| Technical rubber, soles, gaskets | Coated CaCO₃ |
| Paints, paper, putty, construction materials | Uncoated CaCO₃ |
| Animal feed, fertilizer, agriculture | Uncoated CaCO₃ |
With more than 15 years of experience in the production and export of superfine CaCO₃ powder, Tan Ky Mineral Processing JSC is one of Vietnam’s top calcium carbonate manufacturers.
Our Strengths
Own white limestone quarry in Nghe An – CaCO₃ purity > 98%.
State-of-the-art grinding systems from Hosokawa Alpine (Germany).
Certified ISO 9001:2015 quality management.
Products exported to 20+ countries including India, Korea, China, and Malaysia.
Main Products
Coated Calcium Carbonate (CaCO₃ – stearic acid treated)
Uncoated Calcium Carbonate (natural powder)
Superfine and customized particle-size CaCO₃
Contact us today to get a CaCO₃ price quotation : salesmanager@tankymineral.com.vn
