Carbon Black Dispersions
Borregaard LignoTech offers Vanisperse CB and Marasperse CBOS-4, high performance dispersants for aqueous carbon black dispersions.
These products offer:
- Increased milling speed and carbon black loading
- Reduced initial viscosity
- Reduced gelling
- Reduced or eliminated free water
Carbon blacks are produced in an agglomerated form. Milling or grinding processes break up these secondary aggregates to develop the full colouring potential of the black. The structure of the primary aggregates, which do not break down, determines the properties of each grade of black. Low structure blacks have few primary particles in compact structures. High structure blacks have many primary particles fused into long, complex chains. The combination of particle size, structure, and surface oxidation determine the properties such as colouring ability, UV absorption, and conductivity.
Aqueous carbon black dispersions are a convenient means of transporting and administering carbon black without the dustiness and mess associated with the powder form.
In order to fully develop the carbon black’s useful properties, Vanisperse CB and Marasperse CBOS-4 are used to speed up the milling process, increase carbon black loading, and stabilise the dispersions. The optimum dispersant requirement, or DAR, must be determined by experiment to obtain the lowest dispersion viscosity and to prevent flocculation or settling. The higher structure blacks have larger surface areas and require greater proportions of dispersant. They will also give higher viscosities, which limit the carbon black loading values.
How Our Products Work
Vanisperse CB and Marasperse CBOS-4 are amongst the most effective carbon black dispersants available on the market today. They function by adsorbing onto the black and imparting steric and electrostatic stabilisation mechanisms. They are most effective in the pH range between 8 to 10. They function as both grinding aid and dispersion stabiliser, effecting improved fluidity at high carbon black concentrations. They lower both initial viscosity and gelling on standing. They also reduce or eliminate free water. The viscosity of the final dispersion varies with dispersant dosage, as shown in the graph below. Reduced milling times and higher loading both serve to lower manufacturing costs.
Carbon black dispersion applications include latex paint pigmenting, conductive coatings, water-base inks, textile printing pastes, and aqueous graphite dispersions.