There’s only one reason: foreign companies operate factories in China, grinding powder from Chinese ore and selling it to Chinese consumers for thousands of yuan per ton, cash only. They can be number one in the world in this regard. Meanwhile, Chinese companies sell it for a few hundred yuan per ton, fighting tooth and nail for a mere 10 yuan profit.
The core technologies involved are particle size control and surface modification. Therefore, SEED wants to contribute its modest efforts to China’s powder manufacturing industry.
Coupling Agents: The “Bridging Effect” Mechanism
The core mechanism of action of SEED coupling agent is the “bridging effect” — one end of the coupling agent molecule binds to the hydroxyl groups (-OH) on the surface of calcium carbonate powder, while the other end is compatible with organic polymer matrices (e.g., plastics, rubbers, coatings). This addresses the interfacial compatibility issue caused by the hydrophilicity of calcium carbonate powder and the hydrophobicity of organic matrices, and it can be broken down into two specific steps:
Interfacial chemical bonding
The hydrophilic groups (e.g., -Si-OR in silanes, -Ti-OR in titanates) of the coupling agent (silane and titanate types are commonly used) undergo hydrolysis and condensation reactions with the adsorbed water or hydroxyl groups on the surface of calcium carbonate powder, forming stable chemical bonds (e.g., Si-O-Ca bonds) that firmly anchor the agent to the powder surface.
Matrix compatibility enhancement
The hydrophobic groups (e.g., alkyl groups, aryl groups, unsaturated double bonds) of the coupling agent extend into the organic matrix and combine with matrix molecules through physical entanglement or chemical reactions, eliminating interfacial gaps between calcium carbonate powder and the matrix.
The final effects include enhancing the mechanical properties (tensile strength, impact strength) of the composite material, reducing the system viscosity, improving processing fluidity, as well as optimizing the dispersion of calcium carbonate powder in the matrix and reducing agglomeration.
You might be interested in: SEED’s research collaborations
Grinding and Dispersing Agents: Synergistic Action
The core mechanism of action of SEED grinding and dispersing agent is the synergistic effect of adsorption-lubrication-steric hindrance. By reducing the forces between powder particles and between powder particles and equipment, it achieves the dual effects of grinding aid and dispersion, which can be divided into three specific steps:
Adsorption for surface energy reduction
Dispersant molecules (small-molecule organic acids, polyphosphates, and high-molecular polymers are commonly used) adsorb onto the surface of calcium carbonate powder particles via polar groups (carboxyl groups, hydroxyl groups, phosphate groups), replacing the air and water adsorbed on the particle surface, thus lowering the surface energy of the particles and their tendency to agglomerate.
Lubrication for friction reduction
The non-polar long-chain groups of the dispersant extend outward to form a lubricating film on the particle surface, which reduces friction and adhesion between calcium carbonate powder particles, as well as between particles and the mill inner wall/grinding media during the grinding process. This makes the particles easier to grind into finer sizes while cutting down grinding energy consumption.
Steric hindrance for anti-agglomeration
The dispersant molecular chains adsorbed on the surface of the ground fine calcium carbonate powder particles repel each other, forming a steric hindrance barrier that prevents the fine particles from re-agglomerating due to van der Waals forces. This maintains the dispersion stability of the powder and ultimately yields a calcium carbonate product with finer particle size and more uniform particle size distribution.
