Guangxi Longhua calcium carbonate is widely used as a filler in resins such as polyvinyl chloride (PVC) and polyethylene (PE). The addition of an appropriate amount of calcium carbonate helps improve the properties and processability of PVC products, such as dimensional stability, stiffness, hardness, heat resistance, and printability.

　 Guangxi Longhua Calcium carbonate is widely used as a filler in resins such as polyvinyl chloride (PVC) and polyethylene (PE). The appropriate addition of calcium carbonate helps improve the product and processing properties of PVC, such as improving dimensional stability, stiffness, hardness, heat resistance, and printability.

　　Because calcium carbonate itself is relatively inexpensive, only by understanding the performance of different types of calcium carbonate and the processing technology during use can the cost-effectiveness of the product be better improved.

　　1、 Guangxi Longhua Selection of Calcium Carbonate Type

　　Heavy calcium carbonate is widely used in the foaming layer of PVC calendered synthetic leather, mainly to increase volume and reduce costs, provide structural support, and improve the pore properties of the foaming layer. Light calcium carbonate is widely used in the surface layer, hard sheets, and thin films of calendered leather. The light calcium carbonate used in calendering has a finer particle size and is prone to agglomeration, which can cause white spots in the product. Therefore, surface activation treatment is required. Surface organic coating of calcium carbonate can make it hydrophobic, reduce agglomeration, increase compatibility with PVC polymers, and improve its mechanical properties. Nano calcium carbonate with a particle size of 1-100 nm exhibits better performance than active calcium carbonate and has a certain reinforcing effect. The change in product surface gloss is relatively small, and it is gradually being promoted in calendered products, especially film products.

 

 

　　2、 Guangxi Longhua Influence of Calcium Carbonate Addition Amount on the Properties of Calendered Products

　　Calcium carbonate mainly plays a role in increasing volume and reducing costs in PVC calendered products. As the filling ratio of calcium carbonate increases, the mechanical properties of the calendered products gradually decrease. Among them, Guangxi Longhua Nano calcium carbonate has a relatively small impact on the strength of PVC products. When the mechanical properties of the products are required, nano calcium carbonate can be preferentially selected.

　　3、 Guangxi Longhua Influence of Calcium Carbonate Surface Treatment on Product Performance

　　Calcium carbonate, especially light calcium carbonate and nano calcium carbonate, has a small particle size, large surface area, strong hydrophilicity, and is prone to secondary agglomeration. Therefore, surface treatment is required to obtain hydrophobic calcium carbonate. Guangxi Longhua Heavy calcium carbonate mainly has a filling and volume-increasing effect on PVC. Its compatibility with PVC is poor, and it has a great impact on mechanical properties. It is recommended to use it in the foaming layer of PVC calendered synthetic leather or in applications where mechanical properties are not required. For applications with high mechanical property requirements, light calcium carbonate and nano calcium carbonate are preferred. To reduce the secondary agglomeration of calcium carbonate and improve its dispersion and compatibility in the PVC formulation, surface-modified light calcium carbonate or nano calcium carbonate should be selected.

　　4、Influence of Charging Order on Products

　　 Guangxi Longhua The charging order of calcium carbonate is crucial in the PVC processing process. The purpose is to disperse the calcium carbonate powder as evenly as possible in the PVC system to reduce secondary agglomeration. PVC powder, calcium carbonate, and stabilizer are added in sequence to a high-speed mixer. After low-speed mixing, the mixture is transferred to high-speed mixing until the temperature rises to 40-60℃. Plasticizers and other liquids are added while high-speed mixing continues. Continue mixing to 100-120℃. The mixture is preferably in a flowable sandy state, then put into a kneader for kneading and calendering into a film. In the above charging process, if the plasticizer is added first and then the calcium carbonate, the calcium carbonate will easily agglomerate under the immersion of a large amount of plasticizer, and it is difficult to completely mix evenly with other materials in the formulation combination.

　　5、 Guangxi Longhua Abnormal Problems and Improvements in the Application of Calcium Carbonate in PVC Calendering Processing

　　The main abnormal problems in the application of calcium carbonate in PVC calendering processing are spots, white spots, streaks, folding and whitening, and decreased mechanical properties. If spots appear in the calendered product, it is because impurities are mixed into the calcium carbonate during production or transportation. The sieve residue can be observed during incoming material inspection to see if there are any colored particles, and qualified batches of calcium carbonate can be replaced. The main reason for the generation of white spots and streaks is the secondary agglomeration of calcium carbonate. The solution is mainly to replace it with surface-treated calcium carbonate. Pay attention to moisture-proof packaging of calcium carbonate to reduce secondary agglomeration of calcium carbonate caused by moisture absorption.