Applications and differences between talcum powder and calcium carbonate

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Talcum powder and calcium carbonate are both used as fillers, and their main purposes include: 1) increasing dimensional stability (that is, reducing shrinkage), 2) enhancing the stiffness of the material, 3) improving the heat resistance of the material, and 4) reducing the cost of the material. However, they also have their drawbacks: 1) an increase in density, 2) reduced impact toughness when not used properly, and 3) a decrease in the material’s gloss. 　 Like calcium carbonate, talc also comes in different particle sizes, typically 300 mesh, 600 mesh, 800 mesh, 1250 mesh, and 2500 mesh; of course, there are even finer grades available. For use in plastics, 800 mesh and 1250 mesh are the most suitable choices, as they offer the best performance-to-price ratio. The price of talcum powder fluctuates. Generally speaking, it’s not too problematic to determine the price based on the mesh size; for example, 800-mesh talcum powder usually costs between 700 and 850 yuan, while 1250-mesh talcum powder costs between 1000 and 1280 yuan. It is abnormal for the price to be either too high or too low. Regarding the differences in usage between talc powder and calcium carbonate: 1. Talc powder is flaky in shape, which gives it higher stiffness, dimensional stability, and heat resistance, resulting in better reinforcement effects. 2. Calcium carbonate is generally in granular form; therefore, its stiffness and other properties are inferior to those of talcum powder. However, it is cheaper, has a higher whiteness, and has little impact on the impact toughness of plastics. 3. Talc has a nucleating effect on polypropylene, whereas calcium carbonate has little effect in this regard. 4. Calcium carbonate can generally be divided into light calcium carbonate and heavy calcium carbonate, while talc does not have such a distinction; talc is obtained by grinding natural minerals.