The so -called composite calcium carbonate products usually refer to the use of heavy calcium carbonate as the main body (> 50%) and a certain percentage of light -quality calcium carbonate powder. Through the complex and modified technology Sexuality can be well balanced and light, and the advantages of both two are the advantages of the two. While greatly reducing product costs, they expand the application scope of the product and improve the quality of the product.
Complex activated calcium carbonate production process
Based on the production process of heavy calcium dried method, the compound active calcium carbonate can use the following two processes:
★ First, mix a certain granular, proportion of heavy calcium, light calcium mixed grinding → modification → grading;
★ The second is to use heavy calcium and light calcium to grind → grades → modification.
Its characteristics are: simple crafts, small equipment investment, can be packaged directly after the material, especially suitable for the modified processing process of coupling calcium carbonate.
Based on the heavily calcium wetting method, the compound activated calcium carbonate can use the following techniques: calcium and light calcium adjustment to a certain concentration of pulp wetting method → modified → slurry products → dry powder products.
Its characteristics are: wet activation is to treat calcium carbonate particles in the state of liquid phase, which can be evenly covered with calcium carbonate. Surface active agents can be fully dispersed on the surface of calcium carbonate particles through the biting effect and dual electrocable effect. The distance between the particles is increased, the secondary condensation of the particles is reduced during the dehydration and drying process.
Complex activated calcium carbonate surface modification method
The correct choice of a modified agent must not only consider the affinity mixed solubility of the modifier and calcium carbonate and its equipped with pigment powder, but also consider the mixed solubility of other chemical auxiliary agents of the modified agent and the matrix, especially for it for for it for The compatibility effect of the modified calcium and auxiliary materials of the plastic system.
At present, the surface modification methods of calcium carbonate mainly include the modification of the surfactant, the modification of the coupling agent, the reactive monomer and the activated macromolecular modification, and the legal modification of the original point.
(1) Surface active agent modification method
At present, there are many types of surfactants for modified calcium carbonate, large production capacity, and low prices. It can be divided into two categories: fatty acids (salt) and titanate.
(2) Puppet couplet modification method
One end of the coupling molecules is a polar group, which can chemically react with the hydroxyl groups on the surface of calcium carbonate to form a stable chemical key; the non -polar group on the other end is covered on the surface of calcium carbonate particles to make the surface kiss on the surface Oilization can reduce the surface freedom of the particles, improve mixing with resin, and give better physical mechanical properties with better composite materials. At present, the coupling agent used in calcium carbonate is mainly titanate coupling agents and aluminate coupling agents.
(3) Polymer modification method
The polymer can be adsorbed on the surface of calcium carbonate, so that calcium carbonate has a charge characteristics, and forms a physical and chemical adsorption layer on its surface, preventing calcium carbonate particles from gathering blocks and improving decentralization. It is generally believed that calcium carbonate of polymer envelope can be divided into two categories:
One is to adsorb the polymer to the surface of calcium carbonate, and then trigger its aggregation, so as to form a very thin polymerization film layer on its surface;
The other is to dissolve the polymer to add calcium carbonate in an appropriate solvent. When the polymer is gradually adsorbed to the surface of calcium carbonate, the solvent is eliminated to form a envelope.
(4) Original aggregation modification method
In the original polymerization, the particles were first dispersed evenly in the monomer, and then the polymerization was caused by the cause of the cause. Compared with the traditional filling polymer material, the polymerization of the original position ensures the uniform dispersing of the filling particles.