What Is a Color Masterbatch and How Is It Manufactured in the Plant?

The order of blue film for industrial bags started with a new concentrate, purchased because its price per kilogram was lower and the sample plaque looked identical to the previous supplier's. Within a few hours, the pressure ahead of the screen changer rose and the operator stopped the line to replace a screen covered in undispersed blue particles. When the extruder started again, the film showed specks and fine streaks that the customer's inspector detected on the first roll. The next bag, from another lot by the same supplier, arrived in a slightly different shade, and the complaint file closed with a question nobody asked at the time of purchase: how that masterbatch is made.

A color masterbatch is pigment concentrated and dispersed in a carrier resin, supplied in pellet form. Its manufacture moves through formulation, premixing, extrusion, cooling, pelletizing and color control of every lot.

Why two masterbatches of the same shade perform differently in your machine

A color masterbatch is a concentrate of pigment, and frequently of additives, encapsulated in a carrier resin and delivered as pellets. At the processor's machine, it is dosed in a small proportion over the natural resin and transfers its color to it during the process. We covered how to choose it and how to calculate its dosing in previous articles; here we focus on what happens before the bag reaches your warehouse.

Two concentrates can match the same shade on a laboratory plaque and behave very differently in production. The difference originates in manufacturing: how well the pigment agglomerates were broken down, how compatible the carrier resin is with yours, how much moisture the pellet carries and how repeatable the formula is from one lot to the next. Those variables are decided in the manufacturer's plant and paid for in the processor's plant.

Pigment, carrier resin and additives: the three components of the pellet

The pigment provides the color and defines much of the performance: organic pigments deliver brightness and tinting strength; inorganic pigments deliver opacity and resistance to heat and light, and many formulas combine both. The carrier resin is the vehicle that encapsulates the pigment and must melt and blend easily with the customer's resin. Additives such as dispersants, stabilizers or antistatic agents complete the formula when the part requires them, and they travel in the same pellet.

Formulation: the first point where a lot is won or lost

Every masterbatch begins as a written formula, and an error on that sheet cannot be corrected later in the extruder. The formulation defines which pigments go in, in what proportion, on which carrier resin and with which additives, with the customer's final part and process in mind.

Matching against the physical reference or Pantone

When the color is a development, the laboratory starts from the customer's reference: a physical part, a sample of the material in use today, a photograph or a Pantone code. The measuring equipment records the reference instrumentally, and the formulator combines pigments until it is reproduced on the polymer in which it will be used. A match made on a different resin, or approved by eye under office lighting, can fail under store shelf lighting. At Delta Pigmentos, we carry out color matching as an authorized Pantone partner in our Quality Control, Design and Development laboratory.

Carrier resin: compatibility and melt flow index

The carrier resin is selected for its chemical compatibility with the base polymer and for its melt flow index. A carrier that melts much earlier or much later than the customer's resin leaves areas of unincorporated concentrate, and the symptom in the part is color streaks or swirls. For polyolefins such as HDPE, LDPE and PP, the carrier usually belongs to the same family; for engineering plastics, the formulation is tailored to the resin. That is why the laboratory asks for the exact polymer from the start.

Premixing and extrusion: where pigment dispersion is decided

Extrusion is the stage in which powdered pigment becomes color dispersed within the resin. Its quality determines whether the processor receives a pellet that releases color cleanly or a pellet that carries agglomerates all the way to the screen of the processor's own extruder.

Premixing: homogeneity before melting

The components of the formula are weighed and dry blended before entering the extruder. Premixing distributes the pigment, the additives and the carrier resin uniformly, so that every fraction of the material feeding the machine carries the same proportion. A short premix, or a feed system that separates powders from pellets, creates concentration variation within the same lot, and that variation later reappears as a shade difference between bags.

Twin-screw extrusion: shear against agglomerates

Pigments arrive as powder in the form of agglomerates, clusters of particles that must be broken down and coated with resin to develop their full color. In the masterbatch industry, the characteristic equipment for this stage is the twin-screw extruder, whose kneading elements apply shear to the molten material and distribute the pigment through the matrix. The temperature profile, the screw speed and the configuration of the elements are adjusted to each formula: too little energy leaves agglomerates, and excessive temperature can degrade a sensitive organic pigment and shift the shade.

Agglomerates: the defect a color plaque can hide

A poorly dispersed concentrate can deliver the correct shade on a thick plaque and fail in thin film or in fiber, where every unbroken particle becomes visible as a speck, a streak or a gel. On the processor's line, those agglomerates build up on the screen changer, raise the pressure and force production to stop, as in the case described at the beginning. In addition, a poorly dispersed pigment yields less color per kilogram, and the processor ends up compensating with higher dosing. Dispersion quality is therefore reflected in the cost per colored part.

Strands, cooling and pelletizing: the form that defines how the concentrate doses

The molten material leaves the extruder die in continuous strands that pass through a water cooling bath, where they solidify. Surface moisture is then removed and a pelletizer cuts the strands into pellets. These stages define two properties that the processor notices immediately: the moisture and the uniformity of the pellet.

Cooling and drying: moisture under control

A pellet that retains water on its surface or inside releases it in the barrel of the customer's machine. In injection molding, it appears as silver streaks or bubbles; in film, as holes or marks. That is why the time in the bath, the water temperature and the subsequent drying are controlled for each formula, especially in concentrates with a high pigment loading or with mineral fillers.

Pelletizing: uniform size for a stable feeder

Pellets of even size and shape flow the same way in the hopper and in the feeder, and that holds the programmed dosing. A lot with long or thin pellets, or with cutting fines, doses irregularly, especially in volumetric feeders, and the actual percentage drifts from the programmed one. A verification by weight at the start of every shift detects that deviation in time.

Lot quality control: the line between a repeatable concentrate and one that varies

The same product code must deliver the same color on this month's order and on next quarter's. That repeatability is built through lot control that compares every production run against the approved standard before releasing it.

Color measurement against the approved standard

From every lot, a sample is prepared, as a plaque or a film depending on the application, and measured against the standard for the color approved by the customer. If the difference falls within the agreed tolerance, the lot is released; if it falls outside, it is corrected before leaving the plant. Instrumental measurement removes the subjective discussion about the shade and leaves a record that can be consulted.

Certified procedures: traceability of every production run

Our manufacturing procedures are certified under ISO 9001-2015. In practice, the quality management system requires documented procedures and records of every production run, so that a deviation can be traced back to its origin. For the buyer, that record is the assurance that today's approval holds on the orders that follow.

From the laboratory to your machine: how we develop a masterbatch at Delta Pigmentos

Manufacturing is completed at the customer's machine. Our development process has four steps: you send us your shade reference (Pantone code, physical sample or photograph), the polymer, the process and the end use; we review the reference and propose the product with its price and estimated delivery time; you test the sample on your machine, with your material and your conditions; and once the shade is approved, we produce it and ship it anywhere in the country from our plant in Santa Anita, Jalisco.

For commonly used shades, we offer a Basic Color Line of 30 masterbatches for HDPE, LDPE and PP in injection molding, extrusion and blow molding, with recommended options for food contact. When the color or the resin falls outside that scope, the laboratory formulates a custom product with the same manufacturing process and the same lot control.

Frequently asked questions

What information does the laboratory need to develop a color masterbatch?

The shade reference (physical part, Pantone code, photograph or a sample of the current material), the exact polymer, the conversion process and the end use, particularly if there is food contact or outdoor exposure. With that information, we formulate, measure against the standard and send you the sample to validate on your machine.

How long does a color development take, and what is the minimum order?

A color development takes 10 days from sample approval, and the minimum order for a developed color is 100 kg. Every request is reviewed within 24 business hours of receipt.

How can I detect a masterbatch with poor dispersion in my plant?

The most frequent signs are color specks or streaks in thin film, a pressure increase ahead of the extruder screen and higher concentrate consumption than expected to reach the shade. A thin film run at the recommended dosing and inspected against the light reveals the problem before the run is released.

At Delta Pigmentos we have been manufacturing masterbatch in our own plant for 24 years, with our own laboratory, color matching as an authorized Pantone partner and ISO 9001-2015 certified procedures. If you are about to develop a new color, or the concentrate you use today leaves specks, streaks or shade variation between lots, write to us on WhatsApp with your polymer, your process and your shade reference; we will respond with a technical proposal. Every request is reviewed within the following 24 business hours.