masterbatch

Masterbatch is a concentrated mixture used to color or impart properties to plastics. It consists of pigments or additives dispersed in a polymer carrier and designed to be fed into a base resin during compounding or molding. The term covers color masterbatches, additive masterbatches, and specialty variants such as white and black masterbatches.

Two main types are color masterbatches, which supply color through pigments or dyes, and additive masterbatches, which provide processing aids, stabilizers, flame retardants, antistats, or fillers. White, black, and other specialty masterbatches are commonly used to achieve specific performance or appearance goals in finished products.

Common carrier polymers include those compatible with the target resin, such as polyethylene, polypropylene, or polyvinyl chloride. Pigments may be inorganic or organic; additives can include stabilizers, antioxidants, UV absorbers, slip agents, lubricants, anti-block agents, and processing aids. Production typically involves high-shear extrusion to uniformly disperse the pigment or additive in the carrier, followed by pelletizing.

Manufacture and use: Masterbatches are produced by compounding pigments or additives with a carrier polymer, then extruding and pelletizing the resulting material. In processing, masterbatch pellets are fed into the melt stream of the base resin at controlled ratios to achieve the desired concentration and characteristics.

Advantages and considerations: Masterbatches offer precise color control, consistent dispersion, protection of colorants from heat, and simplified resin inventory. They can improve processing stability and product quality. Limitations include higher cost per kilogram, potential compatibility or migration issues with certain resins, and the need for proper selection and processing to ensure uniform dispersion.