Key takeaways
- Masterbatch is a concentrated dispersion of pigment or additive in a carrier resin, let down into natural polymer at a few percent — far safer and more consistent than dosing raw powder.
- The main families are colour, white (TiO2), black (carbon black), additive (UV, antioxidant, antistatic, slip), and filler (calcium carbonate) masterbatch.
- Carrier resin compatibility matters: a PE-carrier masterbatch run in PP usually works, but mismatched carriers cause poor dispersion, specks, and screw issues.
- Specify let-down ratio, carrier resin, pigment type (and any food-contact or lightfastness requirement), and dosing method on the RFQ — a colour match is meaningless without them.
Almost no coloured or performance-enhanced plastic part is made by dosing raw pigment powder into the machine. Powder is dusty, disperses poorly, and is a hygiene and accuracy problem. Instead, the colour or additive arrives pre-dispersed in pellet form — masterbatch — and is blended into natural resin at a few percent. Understanding masterbatch is understanding how a commodity polyethylene or polypropylene pellet becomes a finished, coloured, UV-stable product.
| Type | Active content | Purpose |
|---|---|---|
| Colour | Organic/inorganic pigments | Custom colour matched to a target |
| White | Titanium dioxide (TiO2) | Opacity and brightness — film, caps, packaging |
| Black | Carbon black | Colour, UV protection, pipe and film |
| Additive | UV, antioxidant, antistatic, slip, flame retardant | Changes performance or ageing, often no colour |
| Filler | Calcium carbonate (CaCO3) | Cuts cost and adds stiffness; raises density |
Every masterbatch is pigment or additive dispersed in a carrier polymer, and the carrier is not neutral. A polyethylene-carrier masterbatch will usually run acceptably in polypropylene because the two are reasonably miscible, and 'universal' carriers are sold for mixed-resin shops. But an incompatible carrier disperses badly — you get specks, streaks, and off-shade parts, and in thin film or fibre it shows immediately. For anything demanding, match the carrier to the base resin and say so on the order.
Masterbatch is quoted at a let-down ratio — say 1:25, about 4% addition. A more concentrated masterbatch costs more per kilo but doses less, so the meaningful comparison is cost per finished tonne, not cost per kilo of masterbatch. And the colour the supplier matched is only valid at the stated ratio: dose less and the part is paler, dose more and you waste concentrate and can over-load the melt. Pin the LDR with the colour standard.
A natural resin's food-contact or regulatory status does not survive colouring unless the masterbatch is compliant too. For food-contact parts, pigments and additives must themselves be approved, and for the EU the REACH and RoHS status of every additive matters — certain heavy-metal pigments and some flame retardants are restricted. Treat the masterbatch as a regulated input and require its own documentation, not just the base resin's.
- Type (colour, white, black, additive, filler) and the function required
- Carrier resin, matched to your base polymer where it matters
- Let-down ratio and the colour standard or Pantone/RAL reference
- Pigment chemistry and any lightfastness, heat-stability, or food-contact requirement
- Dosing method (volumetric/gravimetric feeder, or pre-blended) and pellet size
- Compliance documentation — food contact or REACH/RoHS — for the masterbatch itself
A colour match quoted without a carrier, a let-down ratio, and a compliance status is half a quote. Specify all three and the masterbatch becomes a controlled input like any other — the same RFQ discipline that makes resin sourcing predictable applies just as cleanly to the concentrate that colours it.
Frequently asked
Questions on the desk
What is masterbatch?
Masterbatch is a solid concentrate of pigment or additive pre-dispersed in a carrier resin, supplied as pellets. A processor blends a few percent of it into natural (uncoloured) polymer at the machine, so the colour or additive ends up evenly distributed in the final part. It replaces dosing raw pigment powder, which is dusty, hard to disperse, and a workplace-hygiene problem.
What is the let-down ratio?
The let-down ratio (LDR) is how much masterbatch is added to the natural resin — for example 1:25, meaning one part masterbatch to 25 parts base resin, or about 4%. A higher-concentration masterbatch lets you dose less, but the right ratio depends on the pigment loading, the depth of colour wanted, and the dosing equipment's accuracy. The supplier quotes colour at a stated LDR; change the ratio and the colour changes.
Does the masterbatch carrier resin have to match my base polymer?
Ideally yes, but not always strictly. A polyethylene-carrier masterbatch usually runs acceptably in polypropylene because the two are reasonably compatible, and 'universal' carriers exist. But a mismatched or incompatible carrier causes poor dispersion, visible specks, and inconsistent colour. For demanding applications — thin film, fibre, clear parts — match the carrier to the base resin.
What is the difference between colour and additive masterbatch?
Colour masterbatch carries pigment and exists to colour the part. Additive masterbatch carries a functional additive — UV stabiliser, antioxidant, antistatic agent, slip or anti-block, flame retardant, nucleating agent — and exists to change how the plastic performs or ages, often with no visible colour change at all. Many parts use both at once.
General market commentary from the OmniaStrata desk, provided for information only. It is not legal, financial, tax, or trading advice, and it is not an offer or a commitment to any terms. Figures such as price ranges, spreads, financing costs, and credit periods are illustrative market context, not OmniaStrata's rates or terms. Actual contract terms — including price, payment instrument, credit, insurance, and Incoterms — are agreed in writing on a per-transaction basis and at OmniaStrata's discretion. Market conditions change; figures reflect the publication date.