1. Impact on the Appearance of PVC Products
Excessive calcium carbonate residue may cause a decrease in the glossiness of PVC products, with the color becoming darker and uneven. This is because the larger particles or irregularly shaped calcium carbonate fragments in the residue form bumps or depressions on the surface of the PVC products, thereby affecting their appearance quality.
2. Impact on the Physical Properties of PVC
Hardness and Heat Resistance: A moderate amount of calcium carbonate can improve the hardness and heat resistance of PVC, but an excess of residue may increase the hardness and brittleness of the product, while reducing its toughness and impact resistance. This is because the large calcium carbonate particles in the residue create stress concentration points in the PVC, making the product more prone to cracking or breaking under external impact.
Density: The increase in calcium carbonate residue may cause uneven density distribution in PVC, affecting their overall performance. Uneven density may result in deformation or breakage when the product is subjected to stress.
3. Impact on the PVC Processing Process
Flowability: The presence of calcium carbonate residue may affect the flowability of the PVC melt, making it more difficult to control the processing temperature. If the residue is excessive, it may increase the viscosity of the PVC melt, reducing its flowability, which in turn affects processing efficiency and product quality.
Processing Stability: The large calcium carbonate particles in the residue may not bind tightly with the PVC resin, causing them to easily detach or form voids during processing, thus affecting the integrity and stability of the product.
4. Impact on the Cost of PVC Products
Although the price of calcium carbonate is relatively low, excessive residue may increase the scrap rate of PVC products, thereby raising production costs. Therefore, it is essential to properly control the amount of calcium carbonate added and the level of residue in the production process to reduce costs and improve product quality.
In summary, the impact of calcium carbonate residue on PVC processing performance is multifaceted, including aspects such as appearance, physical properties, processing, and costs. Therefore, it is necessary to strictly control the amount of calcium carbonate added and the level of residue to ensure that the quality and performance of PVC products meet the required standards.