The global preparation technology of hydrophobic gas-phase white carbon black presents a "dual track parallel" pattern: chemical modification method dominates the mainstream market, while physical coating method has emerged in specific fields.


The chemical modification method uses silane coupling agent as the core and achieves hydrophobicity through a two-step reaction of "grafting polymerization". The patented technology of Tokugawa Chemicals in Japan shows that by mixing hydrophilic white carbon black with HMDS in a 1:1.2 molar ratio under nitrogen protection at 180 ℃ and controlling the reaction time for 3 hours, a modified product with a hydrophobic angle of 165 ° can be obtained. The key to this process lies in precise control of the amount of silane used - excessive amounts can lead to agglomeration, while insufficient amounts result in insufficient hydrophobicity.


The physical coating method forms a physical barrier on the surface of particles through nanoscale wax like substances. Vorasil developed by Cabot in the United States ™ The series adopts polytetrafluoroethylene (PTFE) micro powder coating technology, which melts and penetrates wax into the pores of white carbon black at a high temperature of 300 ℃, forming a hydrophobic layer with a thickness of 0.5-2 μ m. Although this method has a high cost, it has unique advantages in the field of food contact materials, and its migration capacity meets FDA standards.


Chinese enterprises have achieved breakthroughs in technological innovation. The integrated equipment of "vapor deposition in-situ modification" developed by Hesheng Silicon Industry has shortened the reaction time from traditional 6 hours to 90 minutes and reduced energy consumption by 40%. This technology synchronously injects silane during the hydrogen oxygen flame hydrolysis stage to complete the modification reaction and particle generation, reducing the fluctuation range of the product's specific surface area from ± 15 ㎡/g to ± 5 ㎡/g.