Innovative Application of Highly Filled Calcium Carbonate in Polymer Products
In recent years, continuous advancements in high-filling and high-efficiency dispersion technologies have driven the increasing application of calcium carbonate in polymers. This trend is moving towards improved performance, functionalization, sustainability, and cost-effectiveness, demonstrating enormous development potential.
New Trends in Research and Application of Calcium Carbonate
High-filling calcium carbonate technology has successfully achieved the dual goals of improving performance and reducing costs. However, it is necessary to shift from "passive filling" to "active functionalization".
Studies have shown that the interfacial properties between calcium carbonate powder and polymers are crucial in composite material research and represent a technological breakthrough for achieving active functionalization. These interfacial properties directly affect the mechanical properties, thermal stability, electrical conductivity, thermal conductivity, and other functional attributes of composite materials.
Mechanism of Interface Enhancement Between Calcium Carbonate and Polymer
This indicates that current research on the application of calcium carbonate in polymers still focuses on interfacial reinforcement mechanisms, stress concentration effects, pinning and climbing effects, interfacial porosity, and factors affecting interfacial properties (such as strength and particle size/dispersion).
Interfacial bonding strength: The toughening effect of calcium carbonate on plastics largely depends on the bonding strength at the interface between calcium carbonate and the plastic. Although traditional ester coupling agents, fatty acid salts, and grafting agents can enhance this bonding strength, their effects remain limited.
Particle Size and Dispersibility: Nano calcium carbonate has a larger specific surface area, but its aggregation problem must be addressed. Ultrafine calcium carbonate can significantly enhance materials, but may also alter its processing properties. Conversely, larger particle sizes of calcium carbonate are easier to process, but this convenience may come at the cost of product performance.
Current research findings still have great potential for exploration in both depth and breadth, and high value-added products are constantly emerging.
Application of Calcium Carbonate in Polymers
Calcium carbonate is a functional filler that can significantly improve the mechanical and processing properties of polymer products while reducing costs. It is widely used in various industries, including plastics and rubber.
Plastic
Calcium carbonate is one of the most cost-effective fillers currently available. It is characterized by being non-toxic, non-irritating, odorless, and having high whiteness and medium hardness.
Calcium carbonate powder, when added to plastics, can act as a filler, increasing volume and reducing cost. Furthermore, it enhances various plastic properties, such as thermal stability, toughness, and hardness, and improves light scattering properties, thus achieving opacity and light-blocking capabilities. Moreover, calcium carbonate/PBAT/PLA composites exhibit good compatibility and blending modification potential, balancing toughness and biodegradability. This makes calcium carbonate an ideal choice for filling and modifying biodegradable plastics.
Rubber
Rubber has wide applications in various sectors of the national economy, including transportation, machinery, electronics, and defense. However, rubber also has some significant drawbacks, such as weak intermolecular forces, large free volume, and limited self-crystallization ability. These factors result in lower rubber strength and modulus, as well as poor wear resistance. To overcome these challenges and meet application requirements, the addition of inorganic non-metallic fillers is crucial.
Calcium carbonate is a major filler and reinforcing agent in the rubber industry. Heavy calcium carbonate is primarily used as a filler to reduce costs, while light calcium carbonate offers semi-reinforcing properties, improving the physical and mechanical properties of vulcanized rubber. Furthermore, nano calcium carbonate and modified calcium carbonate offer superior reinforcing properties, along with coloring and whitening effects, allowing them to partially replace more expensive materials such as silica and titanium dioxide. Looking ahead, the trend in rubber applications will increasingly favor the use of nano calcium carbonate and modified calcium carbonate, rather than traditional heavy or light calcium carbonate.
Calcium carbonate is crucial in terms of both quantity and variety of fillers used in rubber products. With continuous advancements in high-filling and high-dispersion technologies, the advantages of calcium carbonate in terms of production, cost, and variety will be more effectively realized.
Tires: The amount of carbon black used in the tread is typically 40 to 50 parts. Little or no non-reinforcing fillers are needed, but a small amount of clay may be added. The inner tube binder can use approximately 20 parts clay or light calcium carbonate.
Adhesive Tape: The amount of carbon black in the tape is typically 25 to 45 parts. Calcium carbonate can be added to various components, ranging from 10 to 113 parts. For flat tape sealant and edge adhesive, magnesium carbonate is used in amounts of 40 and 50 parts, respectively. Barium sulfate is also added to the flat tape adhesive in an amount of 25 parts.
Rubber Hose: The amount of carbon black in the rubber hose is 15 to 45 parts. The amount of calcium carbonate is 33 to 128 parts, and the amount of clay is 20 to 50 parts. In addition, 25 parts of magnesium carbonate and 30 parts of barium sulfate are added to the acid and alkali hose.
Rubber Shoes: The formula includes: 50 parts carbon black for black soles, 50 parts ultrafine activated calcium carbonate (white fireworks), and 40 parts clay; 55 parts carbon black for white soles, 15 parts ultrafine calcium carbonate, and 2 parts titanium dioxide.
Adhesive Tape Products: Calcium carbonate and clay can be used in various adhesive tape products, ranging from 30 to 150 parts. For airtight tapes, 11 parts barium sulfate are added.
Sealing Products: For oil seals, 70 parts silica is recommended. The oil-resistant vacuum seal formulation contains 25 parts silica, 10 parts calcium carbonate, and 30 parts clay. The sealing strip uses 40 parts silica, while the diaphragm consists of 15 parts silica and 54 parts calcium carbonate.
Latex Products: 10 to 15 parts barium sulfate or 5 parts calcium carbonate can be used in latex glove formulations. 20 parts talc can be added to sponge latex formulations, while 2 to 3 parts clay can be added to neoprene latex filament formulations. For porous molded latex formulations, 100 parts clay or 100 to 300 parts calcium carbonate can be used.
