Why Should Calcium Carbonate Undergo Surface Coating2020-12-11

(1) Improve the dispersibility of calcium carbonate

Ultra-fineness is an important way to improve the quality of calcium carbonate, but the smaller the particle size of calcium carbonate, the higher the surface energy, the stronger the adsorption, and the more serious the agglomeration phenomenon.

Through surface coating, the modifier can be oriented to adsorb on the surface of calcium carbonate, so that the surface has charge characteristics. Due to the repulsion of the same kind of charge, the calcium carbonate is not easy to agglomerate, thereby achieving good dispersion in the matrix.

(2) Improve the compatibility of calcium carbonate

Through surface coating, the interface compatibility and affinity between calcium carbonate and organisms can be increased, thereby improving its product performance with rubber or plastic composite materials.

For example: calcium carbonate treated with titanate coupling agent has good compatibility with polymer molecules. At the same time, because the titanate coupling agent can form a molecular bridge between calcium carbonate molecules and polymer molecules, it enhances the interaction between organic polymers or resins and calcium carbonate, and can significantly improve thermoplastic composite materials, etc. The mechanical properties, such as impact strength, tensile strength, bending strength and elongation.

(3) Reduce the oil absorption value of calcium carbonate

Surface coating is an important means to reduce the oil absorption value of powder. After the surface coating of calcium carbonate, the aggregated particles are reduced, the dispersion degree is improved, and the inter-particle voids are reduced. At the same time, the coverage of the surface of the calcium carbonate by the modified molecules reduces the voids in the particles, and this coverage also changes the calcium carbonate. Its surface properties weaken its surface polarity, reduce the friction between particles, and improve lubricity, so the packing becomes tighter, the packing density increases, and the oil absorption value decreases.

(4) Broaden the high-end application market of calcium carbonate

Calcium carbonate without surface coating has poor compatibility, is easy to agglomerate, and has poor application effects, and these shortcomings become more obvious as the dosage increases.

Through surface coating, calcium carbonate has good interface affinity and reduced oil absorption. It can be better used in high-end fields such as plastics, coatings, rubber, paper, sealants, and breathable membranes to improve product quality and further reduce application companies’ Cost of production.

(5) Give calcium carbonate more functional properties

Calcium carbonate without surface coating can only be used as a traditional filling material, and its application field and dosage will be subject to certain restrictions. Through surface coating, calcium carbonate becomes a multifunctional modifier.

Calcium carbonate coated with silica on the surface can partially replace white carbon black and supplement some of the shortcomings of white carbon black; light calcium carbonate coated with metal on the surface can improve certain special properties of rubber products; The calcium carbonate composite material coated with titanium dioxide can replace titanium dioxide to a certain extent; it can be treated with phosphate, aluminate, silicate or barium salt to prepare acid-resistant calcium carbonate.

(6) Increase the added value of calcium carbonate products

At present, my country's ordinary calcium carbonate has overcapacity and competition for low prices is fierce. After surface coating of calcium carbonate, the use effect is significantly improved, the user experience is good, and the product price naturally increases.

(7) Conform to the development trend of calcium carbonate industry

The "Industrial Structure Adjustment Guidance Catalogue (2019)" promulgated by the National Development and Reform Commission has listed ordinary grade calcium carbonate as a backward product, and will continue to increase its elimination in the future.