The dispersion of a color masterbatch directly determines the appearance quality and color stability of plastic parts. Good dispersion means high pigment efficiency, low addition rates, and flawless surfaces. Poor dispersion brings black spots, flow marks, color variation, and reduced mechanical properties.

Why Uniform Dispersion Matters

Pigments do not exist as individual particles. They are agglomerates of thousands of fine particles. If these agglomerates are not fully opened before entering the plastic melt, the consequences are:

·Color specks – Agglomerated pigments form visible defects on the plastic surface.

·Color streaks – Uneven dispersion leads to flow marks.

·Inaccurate color – Non-uniform pigment distribution affects color accuracy.

·Batch-to-batch color variation – Different dispersion levels across batches cause inconsistency.

·Property loss – Pigment agglomerates reduce the mechanical properties of the plastic base material.

The better the dispersion of the masterbatch, the higher the production efficiency and the more stable the surface quality of the plastic part.

Key Factors Affecting Dispersion

Pigment properties – Different pigments (titanium dioxide, organic pigments, etc.) have different particle sizes and agglomeration strengths. Formulations must be customized for each pigment type.

Grinding fineness – Insufficient grinding intensity fails to break up pigment agglomerates, resulting in poor dispersion. Liquid color undergoes multiple grinding stages with high shear, achieving excellent dispersion.

Carrier compatibility – The pigment carrier must be fully compatible with the base resin; otherwise, pigment migration or exudation can occur.

Liquid Color vs. Solid Masterbatch: The Fundamental Difference in Dispersion

The dispersion advantage of liquid color is not simply that "liquid works better than solid". It stems from fundamentally different dispersion mechanisms.

Solid masterbatch is produced by high-temperature mixing and pelletizing of pigments with a carrier resin. The pigments are pre-dispersed to some extent during pelletizing, but they must be melted and re-dispersed in the screw of the injection molding or extrusion machine. This means solid masterbatch is highly dependent on screw shear. If the screw design, speed, temperature, or back pressure fluctuates, the dispersion drifts — which is exactly why many factories experience color instability, black spots, and flow marks when using solid masterbatch.

Liquid color works on a completely different principle. The pigments are already wetted and stabilized in a liquid carrier, with each pigment particle "coated" by a dispersant to prevent agglomeration. Once inside the screw, no shear is needed to "open" the pigments. They simply mix with the molten plastic. Therefore, dispersion is not affected by screw shear fluctuations, and batch-to-batch color consistency is reliably controlled.

What Products Are Suitable for Liquid Color?

High-appearance injection molded parts – Personal care packaging, cosmetic packaging, electronic and electrical housings.

Transparent or light-colored products – Transparency magnifies surface defects, so the dispersion advantage of liquid color is especially evident.

Parts with high requirements for base material properties – Liquid color has extremely low addition rates, minimizing interference with the mechanical properties of the plastic.