Coated Calcium Carbonate
Calcium carbonate that has been coated with a thin layer of stearic acid is known as coated calcium carbonate. Its most notable advantages include a significant reduction in oil absorption, reduced particle aggregation with increased filling of empty spaces, and hydrophobicity.
Compared to uncoated calcium carbonate, coated calcium carbonate also has other advantages such as high spreadability and homogeneity, water resistance, neutrality and good anti-corrosion performance, low dust production in its manufacturing lines, and compatibility with a broad spectrum of polymeric resins.
Calcium carbonate is hydrophilic (i.e., it likes water), but it has no affinity for organic materials like polymers. If uncoated calcium carbonate is mixed with a plastic material, the high surface energy of particles will cause great and, usually, unnecessary friction. The addition of a layer of stearic acid to calcium carbonate reduces friction and makes it hydrophobic. In fact, this coating process can be done in a variety of ways, but the most common is to use stearic acid.
Coated calcium carbonate is primarily used in the plastics, UPVC, polymers, and chemical industries.
Using coated calcium carbonate as a filler makes a significant increase in resistance. It also improves the surface quality and decreases the possibility of fracture when producing plastic items.
As a result, this valuable filler is used in manufacturing the plastic parts and components.
The use of coated calcium carbonate in producing rubber increases the resistance of the final product and diminishes its depreciation and corrosion.
The result is extended longevity of the product. In addition, this substance enhances the brightness and the quality of the surface of these products.
Since natural calcium carbonate is hydrophilic, therefore its application as a filler with polymers will lead to sintering (lump formation) which will result a compromised diffusivity and lower quality of final product. The solution is coating the surface of calcium carbonate with stearic acid.
Coated calcium carbonate leads to an increased resistance in the casing (lining) of polymer pipes and products. Enhanced surface quality of products and pipes’ casing (lining) and a lower possibility of fractures in the final product are other advantages of coating.
Using coated calcium carbonate leads to manufacturing brighter colors. It also enhances the diffusivity of pigments and the quality of the paint, therefore it makes difference to use coated calcium carbonate instead of uncoated calcium carbonates in other different applications like decorative and high-quality paints, resistant plastic equipment (including automobile parts, toys), etc.