How do you choose a dispersant for carbon black?
Carbon black dispersants are additives specifically designed to address the tendency of carbon black to agglomerate and its difficulty in
dispersing within systems such as coatings and inks. Their primary function is to prevent the flocculation and agglomeration of carbon
black particles, ensuring color uniformity and stability.
Mechanism of action: Dispersants adsorb onto the surface of carbon black particles, generating electrostatic repulsion or steric hindrance.
This reduces inter-particle attraction, thereby preventing re-flocculation.
Key effects of dispersants on carbon black:
1. Viscosity reduction: Significantly lowers system viscosity during the grinding process, thereby increasing production efficiency.
2. Stability enhancement: Prevents pigment flocculation, settling, or coarsening during storage, maintaining consistent color strength and hue.
3. Tinting strength enhancement: Optimizes pigment wetting, shortens dispersion time, and improves jetness (blackness) and gloss.
Main types and characteristics of carbon black dispersants:
1. Polymeric hyper-dispersants: Polyester-modified types, block polymers, polycarboxylates, and styrene-maleic anhydride copolymers.
They offer excellent compatibility, strong adsorption, effective steric hindrance, and high stability. Suitable for inks, coatings, automotive
paints, color pastes, and digital inkjet applications; recommended products include RK-4035 and RK-4061C0.
2. Water-based systems: Non-ionic or anionic dispersants, acrylic types, polymeric dispersants, and styrene-maleic anhydride copolymers.
They provide good compatibility, effective de-flocculation, excellent anti-settling properties, and high stability. Suitable for water-based
coatings, inks, color pastes, and inkjet inks; recommended products include RK-4057 and RK-4058.
