Yuan Lei Small Classroom | Use of Nano Calcium Carbonate
Calcium carbonate (chemical formula CaCO3) is a common mineral in nature. It probably includes six mineral forms: amorphous calcium carbonate (amorphous CaCO3), vaterite (vaterite), aragonite (aragonite), calcite (calcite), calcite monohydrate (monohydro calcite) and calcite hexahydrate (ikaite,CaCO3 · 6H2O). It is the main component of natural minerals such as marble, limestone and chalk, it is also a component of shells, coral reefs and pearls. In industry, calcium carbonate as an important inorganic salt chemical products, inexpensive. According to different production methods, calcium carbonate is divided into two categories and multiple models to meet the needs of different industries and different uses. Calcium carbonate powder products made from calcite, marble, chalk, shells, limestone and other raw materials by mechanical crushing and ultra-fine grinding and other physical methods weigh calcium carbonate, expressed as GCC; products made from limestone by chemical methods such as calcination, digestion, carbonation, separation, drying and grading are called light calcium carbonate, expressed as PCC. Common heavy calcium carbonate and light calcium carbonate, usually used as general filler and white pigment.
Next, Yuanlei will show you the use of nano calcium carbonate products:
The addition of calcium carbonate to plastics can increase the volume of plastics, reduce product costs, improve the dimensional stability, hardness and rigidity of plastic products, and improve the processing performance of plastics. At present, a small amount of light calcium carbonate is used in the production and processing of PVC products to improve the tensile strength of PVC products. Because superfine calcium carbonate has the characteristics of high gloss, low wear rate, surface modification and oil repellency, it can be filled in polymers such as polyvinyl chloride, polypropylene and phenolic plastics, and is now widely used in PVC cable fillers.
It can be used as a pigment filler with the advantages of fine, uniform, high whiteness and good optical properties. In the paint, can make the formula in the larger density of the lide powder suspension, anti-sedimentation effect. After the paint is made, the whiteness of the paint film is increased, the gloss is high, and the hiding power is not reduced. This performance makes it widely used in the paint industry. Recent studies have found that ultrafine calcium carbonate has a reinforcing effect and can be used as a coating for preventing stone strikes on automobile chassis. The use of nano calcium carbonate filling coating can also greatly improve its flexibility, hardness, leveling and gloss. By using its blue shift phenomenon, it can be added to the latex, which can form a shielding effect on the coating, achieve the purpose of anti-ultraviolet aging and anti-thermal aging, and increase the thermal insulation of the coating.
The paper industry is the most potential application field of calcium carbonate in China. Can be used for coating processing paper raw materials, especially for high-grade copper board paper. Because of its good dispersion performance and low viscosity, it can replace some clay, can effectively improve the whiteness and opacity of paper, improve the smoothness and softness of paper, improve the absorption performance of ink, and improve the retention rate; nano calcium carbonate is used in high-grade sanitary paper, which can increase the toughness, water absorption and whiteness of the product, and make it safer and more hygienic.
The rubber industry is the main application market for nano-calcium carbonate. Nano-scale ultrafine calcium carbonate has both spatial structure and good dispersion characteristics in rubber, which can improve the reinforcement effect of the material. It can also be used in conjunction with other fillers such as carbon black, white carbon black, clay, titanium dioxide, etc. according to production needs to achieve the purpose of reinforcing, filling, toning, improving processing technology and product performance, reducing the gum content or partially replacing expensive white fillers such as white carbon black and titanium dioxide. Surface modification of nano calcium carbonate with stearic acid and its salts can improve its dispersion in rubber, increase the wettability of the surface of the rubber and calcium particles, and then greatly improve its reinforcement of the rubber. This kind of surface modified nano calcium carbonate, its reinforcing performance can be comparable with white carbon black.
Calcium carbonate can also be used in health products, feed, daily chemicals (cosmetics, soap, facial cleanser, toothpaste), ceramics and other industries. Superfine calcium carbonate products used in the feed industry, can be used as a calcium supplement, increase the calcium content of feed, with high quality and low price, easy to absorb and so on; in daily chemical products, because of its high purity, good whiteness, fine particle size, can replace titanium dioxide as filler; in medicine, chemical fertilizer, pesticide can be used as a carrier material; can also be used in the production of refractory insulation materials, calcium citrate and so on.
Calcium carbonate as a filler in resin ink, in addition to play the role of general ink filler, compared with the traditional ink filler, but also has good stability, high gloss, does not affect the drying performance of printing ink, strong adaptability and other advantages, can replace the higher price of calcium colloid, in order to improve the gloss and brightness of the ink. For high-grade ink, can improve the ink adhesion, reduce the ink on the mechanical wear, suitable for high-speed printing.