Messi Biology Co., Ltd. states that in modern industry, paper has long transcended its traditional scope of writing and printing, evolving into various functional materials with special properties and uses. From the RMB we encounter daily, to filter papers for air and water, and even battery separators crucial for electric vehicle safety, behind these specialty papers lies a key functional additive: magnesium carbonate. Its role in specialty papers is akin to high-end foundation in exquisite makeup, not only improving the “skin texture” (paper structure) but also endowing it with outstanding “expressiveness” (functional properties).
The application of magnesium carbonate in specialty papers is centered on its role as a functional filler. Unlike ordinary cultural paper, which uses calcium carbonate (CaCO₃) as a filler primarily for cost reduction, the choice of filler for specialty papers is based on its unique physical and chemical properties. Magnesium carbonate (MgCO₃) offers a series of irreplaceable advantages: Firstly, its refractive index differs from that of plant fibers, allowing it to effectively scatter light, thereby providing extremely high opacity. This is crucial for anti-counterfeiting papers (such as banknotes, stamps, and tickets), as it effectively prevents images and text from showing through from the back, acting as the first physical barrier in anti-counterfeiting technology. Secondly, nano-sized or specific particle-sized magnesium carbonate particles can precisely control the paper’s porosity and pore size distribution. In filter papers, this controllable porous structure determines filtration accuracy and flow rate; in battery separator papers, it directly influences the unimpeded nature of ion conductive paths.
Its application processes typically fall into two categories: One is as an internal filler, mixed with plant and synthetic fibers during the pulping stage, evenly distributed throughout the paper’s three-dimensional structure, thereby fundamentally altering the paper’s intrinsic properties. The second is as a coating pigment, where its ultrafine powder is formulated into a coating material, evenly applied to the paper surface and finished, thereby significantly improving the paper’s surface smoothness, gloss, printability, and barrier performance.
However, achieving these high-end functionalities demands almost stringent quality requirements for magnesium carbonate. Whiteness is the primary indicator; any slight color difference will affect the visual consistency of the finished paper, and for anti-counterfeiting paper, it is absolutely unacceptable. Particle size and its distribution are at the core of the technology. Magnesium carbonate used for coating must reach micron or even nano levels, with a very narrow distribution, to form a dense, smooth coating layer. For internal fillers, specific particle sizes are also required to ensure high retention and uniform distribution within the fiber network, preventing significant loss in the paper machine’s white water circulation. Furthermore, chemical purity is paramount; heavy metal impurities such as iron (Fe) and copper (Cu) must be present in extremely low concentrations to prevent catalytic fiber aging, which can lead to a decrease in paper strength or yellowing.
Messi Biology Co., Ltd. deeply understands the demands of the specialty paper industry, and its developed high-purity nano magnesium carbonate products have become the preferred choice for many high-end paper enterprises. For coating applications, the company offers nano-grade high-whiteness magnesium carbonate, with an average particle size controllable within the 100-500 nanometer range, whiteness exceeding 98%, regular particle morphology, and easy dispersibility to form stable coatings, imparting excellent printing gloss and color reducibility to coated papers. For internal additive applications, the company’s micron-grade products feature optimal particle size compatibility, good bonding with fibers, high retention rates, and significantly enhance the opacity of base papers for products such as security paper and carbonless copy paper, as well as their writing and printing performance. Particularly noteworthy is that in the cutting-edge field of lithium-ion battery separators, Messi Biology’s high-purity nano magnesium carbonate serves as a recognized excellent porogen. Its purity reaches 99.9%, with extremely low impurity ion content, preventing any contamination that could affect the battery’s electrochemical performance. By adding it during the separator manufacturing process and subsequently removing it through acid washing, uniform, interconnected, and precisely sized micropores are left on the separator, greatly enhancing the battery’s rate performance and safety.
It can be said that from anti-counterfeiting barriers safeguarding national financial security to the “heart” components of the new energy industry, magnesium carbonate, this seemingly ordinary white powder, is playing an indispensable role in the vast realm of specialty papers through technological empowerment, with the solid support provided by companies dedicated to material innovation, such as Messi Biology Co., Ltd.