The price of ordinary CaCo3 powder is much cheaper than plastic, the addition of CaCo3 powder will reduce the cost of plastic products. The CaCo3 powder is called filler.
At present, The main purpose of adding CaCo3 powder is to reduce the cost of plastic. With the improvement of the surface properties of CaCo3 and the shape and particle size are controlled, CaCo3 will gradually become a functional filler that enhances or imparts functionality.
CaCo3 powder is the most commonly used filler in the production and processing of PVC products. Its purpose is to increase the output of PVC products and reduce production costs.
1. Improve the dimensional stability of plastic products
The addition of CaCo3 powder plays a skeleton role in plastic products and has great significant on the dimensional stability of plastic products.
2. Improve the hardness and stiffness of plastic products
CaCo3 powder has high oil absorption value, high rate of hardness improvement. On the contrary, CaCo3 powder with small absorption value of crude oil has a small hardness growth rate. Among soft PVC, heavy calcium carbonate has the lowest rate of increase in hardness, followed by light calcium carbonate.
In general, calcium carbonate powder does not have reinforcing effect on plastics (resin), and calcium carbonate powder tend to penetrated by the resin. Therefore, the normal effect of adding the CaCo3 is to increase the rigidity, elastic modulus and hardness of resin. The tensile strength and elongation decreased with the increase of calcium carbonate content. Depending on the amount of calcium carbonate, the hardness will vary.
3. Improve the processing properties of plastics
The addition of CaCo3 powder can change the rheological properties of plastic. Calcium carbonate powder is usually added in larger quantities to facilitate their mixing with other components and the processing and moulding of plastics.
The addition of CaCo3 powder, especially after surface treatment, can not only improve the hardness of the product, but also improve the surface gloss and smoothness.
The addition of CaCo3 powder can reduce the shrinkage, coefficient of linear expansion and creep properties of the plastic products, creating conditions for plastic processing.
4. Improve the heat resistance of plastic products
Adding the CaCo3 powder to the ordinary plastic products can improve the heat resistance of plastic products. If about 40% CaCo3 powder is added to PP, its heat resistance can be increased by about 200 ℃. When the filling rate is less than or equal to 20%, its heat resistance can be increased by 8~130℃.
5. Improve the astigmatism of plastics
Calcium carbonate powder with a whiteness above 90 has obvious whitening effect in plastic products. In calcium plastic paper, in LDPE and HDPE films, the addition of calcium carbonate powder can achieve astigmatism and extinction, making it suitable for writing and printing. Calcium carbonate powder with better whiteness can also replace expensive white pigments.
6. It can make the product have some special properties
The addition of calcium carbonate powder can improve the electroplating and printing properties of some products. Adding a trace amount of calcium carbonate powder to PVC has a certain flame retardant effect.
7. Reduce the cost of plastic products
The price of ordinary light calcium carbonate and heavy calcium carbonate is far lower than the price of plastics, and the addition of calcium carbonate will reduce the cost of plastic products.
Some points to note :
In the processing of some plastic products, adding a large amount of calcium carbonate powder will reduce the quality of the product, but if inferior calcium carbonate powder is added, the quality of the product will be greatly reduced. Adding the same amount of light calcium carbonate, high-quality light calcium carbonate and low-quality light calcium carbonate will make the performance of plastic products different. Usually, some manufacturers or distributors will mix light calcium carbonate with heavy calcium carbonate and sell it at the price of light calcium carbonate.