Additive Masterbatch: 14 Types, Let-Down Ratios and Selection

An additive masterbatch is a concentrate of one or more functional plastic additives, typically 40-65 wt% active, dispersed in a carrier resin and supplied as pellets that the converter meters into the natural polymer at about 1-5 %. It carries no colour and changes no colour: its job is to give the plastic a property it does not have, from UV resistance to antistatic behaviour, so which type does a given product need, and how much? Suppliers also call it a functional masterbatch, the industry synonym.

Almost every family of plastic additives dosed below a few percent reaches the melt this way rather than as loose powder, because a pellet meters more accurately, raises less dust and stores longer.

This page covers the 14 functional types, the active content and let-down arithmetic that converts a masterbatch dosage into an additive dosage, carrier resin choice, six selection criteria, compounding and feeding, dispersion testing, the REACH and food-contact duties specific to masterbatch, and suppliers.

• 40-65 wt% typical active content in the concentrate (15-80 wt% in extreme commercial cases)
• 1-5 % typical let-down, equal to about 25 kg of masterbatch per tonne of base polymer at 2.5 %
• 14 functional additive masterbatch types covered on this page
• Additive level in the part = active content × let-down, never the masterbatch dosage on its own

What Is an Additive Masterbatch?#

An additive masterbatch is a delivery form, not a chemistry: the same hindered amine light stabilizer or the same erucamide can be bought as a powder, as part of a one-pack blend or as a masterbatch, and only the form changes. The chemistry, the mechanism and the dosage range still belong to the additive's own family page. What the masterbatch page owns is everything about the concentrate itself: what goes into the pellet, how concentrated it is, and how that concentration turns into a dose in the finished part. The parent page on masterbatch covers colour, white, black and filler concentrates alongside this one, since all of them share the same carrier, let-down and dosing logic.

What is an additive masterbatch made of?#

An additive masterbatch has three parts: the active additive at 40-65 wt%, a carrier resin or wax that holds it, and a dispersing aid that wets the additive so it does not re-agglomerate.

• Active additive (40-65 wt% of the masterbatch): the functional substance itself, from a HALS package to a biocide, at the concentration the supplier declares on the technical data sheet
• Carrier resin or wax: wax as a near-universal carrier, or a polymer-specific carrier such as EVA or LDPE for polyolefins and nylon, or polystyrene for ABS, SAN and sometimes PC
• Dispersing aid or wax: micronised waxes such as Clariant's Ceridust range and metallocene polyolefin waxes such as Licocene wet and disperse the additive; Licocene also works as a carrier in its own right, permitting higher loadings, lower processing temperatures and reduced shear
• Optional co-additives: a small antioxidant dose to protect the concentrate during its own compounding pass, without changing the declared active content of the functional additive

Our source library holds no active-content figure for most individual additive masterbatch types; 40-65 wt% is the general masterbatch range, and the exceptions are named below. The waxes and polyglycerol esters that wet the additive are covered under dispersing agents for plastics and masterbatch, including Palsgaard's Einar 103 polyglycerol ester, used at 1-5 % of a colour masterbatch formulation.

What is the active content of an additive masterbatch?#

Active content is the weight fraction of the actual additive in the masterbatch pellet, and it usually sits between 40 and 65 wt%, with the full commercial range running from about 15 to 80 wt%. It is the number a buyer needs before any let-down calculation, since two masterbatches at the same percentage can deliver very different doses if their active contents differ. Active content is a supplier-specific value: read it off the technical data sheet, not off a category average.

Three documented exceptions sit outside the general range: a fluoropolymer processing aid is supplied as a 2-5 % masterbatch, well below the general range, because the active fluoroelastomer works at ppm level; an azodicarbonamide foaming masterbatch can hold up to about 70 % active (Eiwa Panthlene H7351, 70 % azodicarbonamide in a PE carrier); and a North American black pipe masterbatch standardises on 35 wt% carbon black, avoiding loadings above 40 wt% because dispersion degrades. Active content is defined in the glossary with its conversions.

Additive masterbatch vs color, white, black and filler masterbatch#

An additive masterbatch carries a functional additive and is meant to be invisible, while a color masterbatch carries pigments and dyes and a filler masterbatch carries mineral filler at loadings high enough to change the density and cost of the compound. A white masterbatch is simply a colour masterbatch built around titanium dioxide, and a black masterbatch around carbon black. Table 1 sets out what each concentrate type carries, how concentrated it typically is and whether it shows in the finished part.

Table 1. Masterbatch types compared

Cells marked as not stated are left out rather than estimated; each sibling page carries its own verified figures.

Pigment loadings and colour-matching rules are on color masterbatch, and CaCO3 loadings, particle size and carrier specifics are on filler masterbatch.

Combination products also exist commercially: at least one major masterbatcher sells color-and-additive combination masterbatches, which is why a converter can end up running a single concentrate instead of two. This is an observed commercial practice, not a recommendation, and it does not change the arithmetic below. The 35 wt% carbon black standard used in pressure pipe compounds is explained in full on black masterbatch.

What Are the 14 Types of Additive Masterbatch?#

The 14 most common additive masterbatch types are UV stabilizer, antioxidant, slip, antiblock, antistatic, antifog, anti-scratch, desiccant, processing aid, flame retardant, foaming agent, antimicrobial, oxygen scavenger and laser marking masterbatch. They are grouped by function below: stabilizers, then surface and optical modifiers, then processing modifiers, then regulatory and functional specialties. Table 2 gives the level the finished part needs where our source library holds a verified figure, and the page where the chemistry is explained.

Table 2. The 14 additive masterbatch types

The level column is the additive level in the finished plastic, not the masterbatch dosage; divide by the masterbatch's declared active content to get the let-down. Ranges are supplier technical-data-sheet values and trials decide the final level. Empty cells are facts our source library does not yet hold, left empty rather than estimated.

Request quotes for additive masterbatch: state the type, active content, carrier resin, base polymer, volume and country, and send it to several producers at once with the plastic additive supplier finder.

1. UV stabilizer masterbatch#

UV stabilizer masterbatch is the most searched additive concentrate of all, because agricultural film, woven sacks and outdoor mouldings all need hindered amine light stabilizers in the finished part and almost nobody meters HALS powder by hand. HALS trap the free radicals that photo-oxidation generates, while UV absorbers convert incoming UV radiation to heat before it reaches the polymer backbone; the two mechanisms are often combined in a single concentrate. In PP the part needs 0.05-1.4 wt% HALS, and in PE the range runs from 0.05-0.6 wt% in thick sections to 0.1-1.0 wt% in film.

A 50 % HALS masterbatch let down at 1 % gives 0.5 wt% HALS in the part (0.50 × 1 % = 0.5 %), which is arithmetic, not a product recommendation. Commercial examples include Syensqo's Cyasorb UV-3853, sold as the masterbatch grades UV-3853PP5, UV-3853PP4 and UV-3853PE5, and Mayzo's BLS 1880PP, a masterbatch version of its BLS 1718 HALS dosed at 0.1-3 %. Class by class, UV stabilizers for plastics explains what is inside a UV concentrate and how HALS and absorbers are combined.

2. Antioxidant and processing-stabilizer masterbatch#

An antioxidant masterbatch is how most converters reach the 500 to 1,500 ppm of stabilizer a compound needs, because gravimetric feeders lose accuracy at those levels when dosing loose powder. A typical package pairs a phenolic antioxidant with a phosphite, since polyolefins need Irganox 1010 at 0.05-0.4 wt% and Irgafos 168 at 0.05-0.2 wt%, with the phosphite-to-phenol ratio running from 1:1 to 4:1 depending on the melt-processing severity.

Ampacet, in its supplier FAQ, cites 2.5 % of an antioxidant masterbatch to reach 1,000 ppm of active antioxidant in the part, which corresponds to a 4 % active concentrate (0.04 × 2.5 % = 0.1 % = 1,000 ppm). Phenolic antioxidants can discolour a compound through over-oxidation, pigment interaction (especially with TiO2), cardboard yellowing in storage and gas fading from NOx exposure, which is why phenol-free antioxidant masterbatches exist and yellow less. For recyclate, Knoben et al. (2025) report a restabilization package of 500 ppm of primary antioxidant plus 1,000 ppm of secondary antioxidant. Phenolic and phosphite grades and their ratios are on antioxidants for plastics.

3. Slip masterbatch#

Slip masterbatch delivers 500-1,200 ppm of erucamide or oleamide into film so that the coefficient of friction drops far enough for the reel to unwind and the bag to open. BOPP and BOPE lines run both migrating and non-migrating slip masterbatches as standard, alongside antiblock, antistatic and antifog concentrates. The masterbatch form does not change the underlying blooming physics: oleamide blooms to the surface quickly while erucamide blooms slowly, a difference documented by Nouman et al. (Polymer Degradation and Stability, 2017), and the slow-blooming erucamide is generally preferred for roll stock.

Bloom times and coefficient-of-friction targets are on slip additives for plastic film. Synthetic silica antiblock can adsorb slip additives and retard their migration, one reason the two types are ordered together.

4. Antiblock masterbatch#

Antiblock masterbatch carries a hard mineral, usually diatomaceous earth, talc, synthetic silica or calcium carbonate, that roughens the film surface enough to stop adjacent layers sticking together. The level the part needs depends on the mineral: diatomaceous earth or talc runs 2,500-10,000 ppm, while calcium carbonate runs 2,500-20,000 ppm. Antiblock is a standard type on BOPP and BOPE film lines, alongside slip, antistatic and antifog, and it competes with the slip amide for the same surface.

Published let-down figures for antiblock masterbatch specifically are not verified in our source library, so this page states the active level the part needs and leaves the buyer to divide by the concentrate's declared active content. Mineral choice and particle size are compared under antiblock additives.

5. Antistatic masterbatch#

Antistatic masterbatch moves a polyolefin from about 1e15-1e16 ohm of surface resistivity into the antistatic window of 1e9-1e13 ohm, either with a migrating antistat that needs humidity or a permanent polymeric antistat that does not. Migrating antistats such as glycerol monostearate and ethoxylated amines bloom to the surface and pick up atmospheric moisture to conduct, while permanent types conduct through the bulk; above 1e14 ohm a surface counts as insulative, per Ampacet's definition.

Two buying traps no ranking page mentions: a migrating antistat needs about two days to build a working monolayer on LDPE and LLDPE, and glycerol monostearate gives only 1-2 months of service life. Two thresholds matter for electronics packaging: NFPA 99 requires static decay below 0.5 seconds (5 kV to 10 % residual) at 50 % relative humidity, or resistivity below 1e11 ohm; MIL-PRF-81705D requires static decay below 2.0 seconds (5 kV to 0 % cutoff) at 12 % relative humidity and resistivity below 1e12 ohm. Migrating and permanent chemistries are compared on antistatic agents for plastics.

6. Antifog masterbatch#

Antifog masterbatch puts a non-ionic surfactant into the sealant layer of a lidding or wrap film at roughly 0.5-2.0 % of that layer, so condensed water spreads into a transparent sheet instead of scattering into droplets. Palsgaard's Einar range documents the levels: Einar 618, a cold-fog grade, runs 1.0-1.5 % in PP random copolymer film and 1.5-2.0 % in PP homopolymer film, while Einar 422, a hot-fog grade, runs 0.5-1.0 % and 1.0-1.5 % respectively. PP generally needs three to five times the antifog loading of PE, and homopolymer PP needs more than random copolymer, because crystallinity controls migration speed.

Antifog is often placed only in the thin sealant skin of a coextruded film rather than through the whole structure, and a lamination step can extract it, which makes extraction resistance a real selection criterion. Cold-fog and hot-fog grades are compared under antifog additives.

7. Anti-scratch and siloxane masterbatch#

Anti-scratch masterbatch is almost always bought as a concentrate, because the ultra-high-molecular-weight siloxanes and migrating slip amides that deliver it cannot be metered any other way at their working levels. Three mechanisms are in commercial use: migrating slip amides lower the surface coefficient of friction so a stylus glides instead of ploughing, siloxane masterbatches give permanent, non-migrating lubricity, and polar-grafted polymers raise surface hardness and filler adhesion to reduce talc whitening. The amide route is dosed at 0.2-0.5 wt% in the part.

The siloxane route's active content and let-down are not yet verified against a supplier data sheet, so this page publishes no number for it; the amide range above is the only dosage stated here. The main market is automotive interior PP and talc-filled PP. Siloxane and amide routes are compared on anti-scratch additives for plastics.

8. Desiccant (moisture scavenger) masterbatch#

Desiccant masterbatch binds the water that recycled or filler-heavy polyolefin carries into the extruder, at 1-5 % of the throughput, and calcium oxide does it by chemical reaction rather than by adsorption. Calcium oxide chemisorbs water irreversibly (CaO + H2O gives Ca(OH)2), which Sängerlaub et al. (Materials, 2019) contrast with the reversible physisorption that silica gel and zeolite desiccants rely on. One supplier states a dosing rule of 1 % masterbatch per 0.15 % moisture in the polymer.

The active calcium oxide content of commercial desiccant masterbatches is not established in our source library, so this page states no loading figure, and desiccant masterbatch does not replace drying for PET or PA. Chemistry, dosing rule and limits are on desiccant masterbatch.

9. Processing aid (PPA) masterbatch#

Processing aid masterbatch is the clearest case for the delivery form: a fluoroelastomer works at a few hundred ppm, so it is bought as a 2-5 % masterbatch and let down to reach that level. The fluoroelastomer droplets coat the die wall and induce interfacial slip, eliminating sharkskin melt fracture; Yang et al. (2025) document the time-to-clear a line needs before the effect appears. Under 21 CFR 177.1520, the extrusion aid grade (65-71 % fluorine) is capped at 0.2 wt% and the processing aid grade (87 % or more VDF) at 1.0 wt%, both maximum use levels on the finished polymer, conditions of use B through H.

From 12 August 2026, the EU Packaging and Packaging Waste Regulation, Regulation (EU) 2025/40, Article 5(5), blocks food-contact packaging that contains 50 ppm or more of total PFAS, polymeric PFAS included, which is why PFAS-free processing aid masterbatches, based on polyether-grafted PDMS, boron nitride, TPU or PFAS-free polyolefin and ester chemistries, now exist alongside the fluoroelastomer route. Fluoropolymer and PFAS-free routes are compared on polymer processing aids.

10. Flame retardant masterbatch#

Flame retardant masterbatch works only where the flame retardant is effective at a few percent, because a UL 94 V-0 polypropylene needs 22-30 wt% of intumescent ammonium polyphosphate and a halogen-free flame-retardant cable compound needs about 60 wt% of mineral filler, which no let-down ratio built on a 1-5 % concentrate can deliver. This is the honest limit of the delivery form: at high loadings the flame retardant essentially becomes the compound, not an additive dosed into it. Where the concentrate route does work is set out on flame retardant masterbatch.

11. Foaming agent masterbatch#

Foaming agent masterbatch is one of the few types with a published active content: azodicarbonamide concentrates reach about 70 % active in a polyethylene carrier, with decomposition starting near 200 °C, and an ABS-carrier grade also exists commercially. In the US, azodicarbonamide is capped at 5 wt% of the finished foamed polyethylene under 21 CFR 178.3010, and at 2 % of a closure-sealing gasket composition generally, or 5 % in a polyethylene gasket, under 21 CFR 177.1210; these are regulatory ceilings, not technical dosage recommendations. Chemical and inorganic foaming concentrates are compared on foaming agent masterbatch.

12. Antimicrobial masterbatch#

Antimicrobial masterbatch dilutes a biocide that works at 0.001-1 wt% of the part, which puts it firmly in the range where a concentrate is the only practical delivery form. Silver-zinc zeolite is the most documented biocide class; in a 2016 study, Le et al. reported about 100 % antimicrobial efficiency in polypropylene at 80-160 ppm silver, alongside a drop in elongation at break from 562 % to 443 %. An article made from an antimicrobial masterbatch that claims a biocidal function carries its own duties under the EU Biocidal Products Regulation as a treated article, a topic covered in full on the hub. Biocide chemistry and treated-article duties are on antimicrobial additives for plastics.

13. Oxygen scavenger masterbatch#

Oxygen scavenger masterbatch is dosed into the PET preform wall or into the closure, and the choice between the two decides whether the recycler sees the additive at all. Commercial PET scavenger concentrates are non-nylon polyester types, such as the Amosorb 4020 series, or MXD6 with a cobalt catalyst; the 4020L grade is compatible with up to 100 % recycled PET. An alternative design places the scavenger entirely in a two-layer HDPE or PP closure so nothing sits in the PET wall, which avoids yellowing the recycled resin. For recyclability, the EPBP guideline caps MXD6 at 5 % in clear PET and 6 % in coloured PET. Wall and closure routes are compared on oxygen scavengers for plastic packaging.

14. Laser marking masterbatch#

Laser marking masterbatch makes a plastic that would otherwise ignore a laser beam take a permanent, ink-free code, which is why it appears in unique device identification for medical devices, food-packaging lot codes, wire and cable part numbers and automotive safety parts. It is used across PP, PC/ABS, PA and POM, and depending on the formulation the mark shows either white or dark against the base colour. Our source library holds no verified dosage or composition figure for the common commercial laser marking masterbatch grades, so this page states neither. Polymer suitability and mark colour are covered under laser marking additives.

How Much Additive Masterbatch Do You Add? Let-Down Ratio and Active Content#

Additive masterbatch is normally added at 1-5 % of the base polymer, but that percentage on its own says nothing about the part: the additive level in the finished plastic is the masterbatch active content multiplied by the let-down. At 2.5 %, that works out to 25 kg of masterbatch per tonne of base polymer, a figure repeated across the industry as a rule of thumb. Two masterbatches can carry the same let-down and deliver completely different doses if their active contents differ, which is the single most common source of confusion on ranking pages that quote a let-down without ever naming a basis.

additive in the part (wt%) = active content of the masterbatch (as a fraction) × let-down (%)
additive in the part (ppm) = active content of the masterbatch (as a fraction) × let-down (%) × 10,000

Run your own active content and target additive level through the let-down ratio calculator, which returns the let-down in both conventions.

How is a let-down ratio written and calculated?#

A let-down ratio is written in two ways that look alike and mean the same thing: as a percentage of masterbatch in the blend, or as parts of natural resin per part of masterbatch, so 5 % is the same as 19:1. Ampacet's supplier documentation uses both conventions in one sentence, writing "5 % (19:1)" and "6.5 % (14:1)"; a coloured pressure-pipe masterbatch at 2-4 % is written 49:1 to 24:1. Both conventions are in daily use and are not the same number to read at a glance, so this site always prints both.

Table 3. Let-down conversion (masterbatch in the blend, both conventions, and the resulting additive level)

The last two columns are arithmetic, not product data: they show what the same let-down delivers from a 4 % and a 50 % concentrate. The 2.5 % row matches both the 25 kg per tonne rule of thumb and Ampacet's 2.5 % figure for 1,000 ppm of active antioxidant.

Conversion between phr, wt%, ppm and let-down is worked through step by step on the formulation hub, the reference to use when a data sheet quotes phr instead of a let-down percentage.

Why the masterbatch dosage is never the additive dosage#

Two masterbatches added at the same 2.5 % can leave one part with 1,000 ppm of additive and another with 1.25 wt%, a factor of more than twelve, purely because their active contents differ. The antioxidant case: 0.04 × 2.5 % = 0.1 wt%, which is 1,000 ppm, matching the Ampacet figure above. The black pipe case, for comparison, since it is a colour masterbatch: a 35 % carbon black masterbatch let down at 5-6.5 % gives 1.75-2.3 wt% carbon black, inside the 2-2.5 wt% that ISO 4427 requires for PE pressure pipe.

A let-down that looks harmless can cross a legal limit. Carbon black in plastics is capped at 2.5 % w/w of the polymer for EU food-contact use and 2.5 % by weight in the US, so a 40 % concentrate let down at 7 % already puts 2.8 wt% carbon black in the part, over both limits.

Which Carrier Resin Suits Your Polymer?#

The carrier resin has to melt and flow like the polymer it is going into, because at a 1-5 % let-down it becomes a real ingredient of the compound rather than a passive vehicle. A carrier mismatch shows up as gels, poor optical clarity or a weak weld line, because the carrier does not fully merge with the base resin in the melt.

Table 4. Carrier resin by base polymer

Carrier choice is a supplier decision that the buyer has to check. This table lists the carriers our source library records, not an exhaustive compatibility matrix.

The universal, wax-carried route trades compatibility breadth for a lower permissible loading, because the wax itself stays in the finished part at the let-down level. Carrier chemistry and melt-index matching are covered on masterbatch carrier resins, and the wax-only route has its own dedicated page on universal masterbatch.

How Do You Choose an Additive Masterbatch? 6 Criteria#

Choose an additive masterbatch on 6 criteria in this order: the additive level the part needs, the active content and the let-down that follows from it, carrier compatibility, interactions with the rest of the formulation, the regulatory status of every component, and evidence of dispersion quality.

1. The additive level the part needs. Start from Table 2 or the family hub for the additive in question, since the target level is fixed by the application, not by the masterbatch.
2. Active content and the resulting let-down. A masterbatch is only comparable to another once its active content is known, because the same target level can come from very different let-downs.
3. Carrier compatibility with the base polymer and its melt index. A carrier that does not match the base resin's flow shows up as gels or weak spots, particularly in pressure pipe, where the carrier's melt index is specified directly.
4. Interactions with what is already in the compound. Thioesters antagonise HALS, acids deactivate basic HALS, and talc and silica adsorb antioxidants and HALS onto their own surface; low-treated TiO2 with a phenolic antioxidant is a documented cause of pinking.
5. The regulatory status of every component for the intended end use. REACH registration, EU 10/2011 compliance and 21 CFR status apply to the additive and the carrier both, not only to the finished polymer.
6. Evidence of dispersion quality. A supplier's microdispersion rating or filter pressure value should be requested before a first production trial, not discovered afterward.

The full 7-step framework is on how to select plastic additives, which extends this list to cover neat powder and one-pack selection as well.

How Is Additive Masterbatch Made and Fed to the Machine?#

Additive masterbatch is made by melt compounding on an extruder and fed to the converting line by a metering feeder matched to the required dosing accuracy. Compounding mixes the carrier and the active additive in the molten state: feeding, conveying, heating through the barrel zones, cooling the strands in a water bath or spray, then pelletising. A co-rotating twin-screw extruder gives higher axial velocity and better dispersive and distributive mixing than a single-screw machine, which is why it dominates masterbatch production. Each production step is described on how masterbatch is made.

Compounding routes: premix and split feed#

Two routes dominate: a premix, where everything is blended first and fed together, and a split feed, where the additive enters through a side feeder after the carrier has already melted. In a premix, all components are blended homogeneously before the twin-screw extruder and fed by a single volumetric feeder. In a split feed, the polymer pellets enter the main feed throat while the additive or pigment is metered in downstream, after the melting zone, by a dedicated twin-screw side feeder, which gives gentler wetting and fewer agglomerates than blending everything cold. Screw configurations and mixing regimes are covered under plastic compounding.

Feeding and dosing on the converting line#

On the converting line the masterbatch is metered by a gravimetric loss-in-weight feeder, because volumetric dosing cannot hold a ppm-level target through pellet-density variation between lots. Gravimetric accuracy is what makes ppm-level additive dosing practical at all, whether the additive arrives as masterbatch or as a one-pack blend. Liquid masterbatch is the alternative delivery form on the same line, dosed by a peristaltic pump, which gives highly accurate metering and fast colour or type changeovers between production runs. Pump dosing is compared with pellet dosing on liquid color concentrates.

What goes wrong: gels, streaks and poor dispersion#

The most common masterbatch defect is a gel in the film, and an un-melted concentrate pellet or an under-dispersed additive is one of its four classic sources, alongside degraded or crosslinked polymer, high shear or long residence time in the barrel, and a weak antioxidant package that lets the melt oxidise. The fix is to identify the source first, then address it: lower the temperature, raise throughput to cut residence time, revise the screw design, tighten the screen pack, switch to smaller pellets or change the carrier.

Radebe et al. (2022) measured a 60 wt% LLDPE calcium carbonate masterbatch at roughly three times the melt viscosity of the neat polymer, and showed that 3 wt% wax plus 1.0 wt% zinc stearate brought it back to just above the neat resin, a demonstration of how a lubricant package changes a concentrate's own processability. Gels, streaks, plate-out and blooming are diagnosed under troubleshooting additive-related defects.

How Is Additive Masterbatch Tested?#

Four things are tested on an additive masterbatch: dispersion quality, melt flow compatibility, the active content the supplier declares, and the property the additive is meant to deliver in the finished part.

• Dispersion quality. Black masterbatch dispersion is rated on a microdispersion scale from 1 to 5, with 1 the best, checked on about 1.5 mil PE film and reported per lot; pipe-grade dispersion is rated to ISO 18553, and filter pressure value serves as a second measure alongside colour strength.
• Melt flow compatibility. Melt flow rate, to ISO 1133 or ASTM D1238, shows whether the carrier's flow behaviour tracks the base resin closely enough to avoid gels and weak welds.
• Declared active content. Taken from the supplier's certificate of analysis; checked independently by extraction or thermogravimetric analysis only where a validated method exists for that combination, since no single standard method covers every type.
• Function delivered. Tested against the family's own standard: oxidation induction time for antioxidants, accelerated weathering for UV stabilizers, surface resistivity and static decay for antistats, coefficient of friction for slip agents, haze for clarifiers.

Microdispersion ratings and the filter pressure value are explained on dispersion testing of pigments and masterbatch.

Which Rules Apply to an Additive Masterbatch?#

An additive masterbatch is legally a mixture, not a polymer, so the substances inside it carry their own duties: REACH registration follows the additive even when it crosses the EU border dissolved in a carrier resin, EU and US food-contact rules limit what ends up in the finished plastic, and in both systems the limit sits on the finished part, never on the concentrate. The full compliance picture, across every additive family, is mapped under plastic additive regulations.

REACH: the additive inside the masterbatch needs its own registration#

Importers regularly assume that buying a masterbatch instead of a powder moves the REACH registration duty onto the supplier, and outside the EU it does not: the additive is a substance in a mixture and needs its own registration at 1 tonne a year or more per manufacturer or importer, under Regulation (EC) No 1907/2006. Polymers are exempt under REACH Article 2(9), and the full REACH revision that would have added polymer registration was set aside by the European Commission on 27 April 2026, so that exemption stands. Registration duties by role are set out on REACH and plastic additives.

The SVHC Candidate List held 253 entries as of 22 September 2026, last updated 4 February 2026, and inclusion triggers a supply-chain communication duty, never a ban. The one place EU law treats a masterbatch as its own regulated object is REACH Annex XVII entry 23, restricting cadmium below 0.01 % by weight in a defined list of plastics, including LDPE, "except for coloured masterbatch," under Regulation (EU) No 494/2011, in force from 10 December 2011. Every listed additive is tracked on the SVHC Candidate List.

Food contact: the limit applies to the finished plastic, not to the concentrate#

Every food-contact limit in EU Regulation (EU) No 10/2011 and in the relevant parts of the US 21 CFR is set on the finished plastic, never on the masterbatch, so the compliance question is always what the let-down leaves in the part. The Union list in Annex I Table 1 covers monomers, additives and polymer production aids by FCM number, with a generic specific migration limit of 60 mg/kg under Article 11(2) and an overall migration limit of 10 mg/dm2, or 60 mg/kg for infant food, under Article 12; colorants are not on the Union list. In the US, 21 CFR 174.5 requires an amount not more than reasonably required, suitable purity, and good manufacturing practice; per-polymer limits such as 21 CFR 178.2010 are maximum use levels in the finished polymer, never recommended dosages, and this page never writes "FDA approved."

Since 16 December 2025, a masterbatch that is not itself compliant for its intended food-contact use must say so in its own Declaration of Compliance, a duty introduced by Regulation (EU) 2025/351 (Official Journal, 24 February 2025), which also covers purity, reprocessing of off-cuts and scrap, testing and good manufacturing practice; products placed on the market before 16 September 2026 may stay in circulation until stocks run out. No ranking page mentions this. SML, OML and the Declaration of Compliance are explained on EU 10/2011, and how the 21 CFR parts fit together is on FDA food contact rules for plastic additives.

Who Supplies Additive Masterbatch?#

Additive masterbatch comes from a small group of global compounders, led by Ampacet, Avient, Tosaf, Cabot and Teknor Apex, and from several hundred regional producers, many of them based in India, Vietnam and China. Table 5 lists the additive masterbatch brand lines our source library records for each of the larger, better-documented producers.

Table 5. Producers and their additive masterbatch brand lines

Brand lines are taken from our source library. This is not a ranking and no company paid for inclusion; see our methodology.

Buyers should compare concentrates by active content and carrier resin, not by let-down ratio alone, because a lower recommended let-down usually just means a higher active content, not a more effective additive. This page states no masterbatch market size: verified figures could not be confirmed from primary sources. Plants, regions and product ranges are listed under masterbatch manufacturers, and the dedicated buyer directory is additive masterbatch manufacturers and suppliers.

Request quotes for additive masterbatch: state the type, active content, carrier resin, base polymer, volume and country, and send it to several producers at once with the plastic additive supplier finder.

What Are the Alternatives to an Additive Masterbatch?#

A masterbatch is one of four ways to get an additive into a polymer: as neat powder, as a dust-free one-pack blend, as a masterbatch, or as a liquid dosed at the throat. Additive delivery forms in general also include free-flowing granules, pastilles, flakes and prills, each suited to a different feeder type. Units, dosage and processing across every additive family sit under plastic formulation and additive processing.

Masterbatch vs one-pack blends vs neat additive powder#

A one-pack blend sits between powder and masterbatch: it is a pre-weighed, dust-free combination of the additives themselves, with no carrier resin to dilute the compound. Commercial examples include Baerlocher's PVC stabilizer and lubricant one-packs, Songwon's OPS blends and Rianlon's U-pack antioxidant blends, with Songwon offering fixed phosphite-to-phenolic ratios of 1:1, 2:1, 3:1 and 4:1. The trade-off in one sentence: the masterbatch adds 1-5 % of carrier to the formulation, the one-pack does not, and the neat powder needs feeder accuracy that many converting lines do not have at ppm-level targets. Restabilization dosages for recyclate, using the primary-plus-secondary antioxidant approach described above, are on additives for recycled plastics.

Masterbatch vs pre-coloured compound and liquid dosing#

A pre-coloured or pre-compounded resin arrives ready to mould, with the additive already dispersed by the compounder, which removes the converter's dosing risk entirely and adds one supply-chain step in exchange. Compounders such as Teknor Apex sell ready-to-mould compounds and are themselves buyers of the same additives covered on this page. Liquid dosing by peristaltic pump is the other alternative, offering accurate metering and fast changeovers without a carrier pellet at all. The film masterbatch set used on packaging lines is listed under additives for packaging film.

What is the difference between an additive and an additive masterbatch?#

An additive is the chemical that does the work; an additive masterbatch is that same chemical pre-dispersed at 40-65 wt% in a carrier resin so it can be metered as pellets rather than handled as powder. The chemistry and the dosage the finished part needs are identical either way. Suppliers and some search results use "functional masterbatch" as an exact synonym for the same product.

Can you run two masterbatches at the same time?#

Yes: running a colour masterbatch and an additive masterbatch together is normal practice, and suppliers also sell combined colour-and-additive concentrates for converters who want a single feed stream. The one honest caveat: each concentrate adds its own carrier to the compound, so two masterbatches dosed at 3 % each put 6 % of foreign carrier resin into the part, which is worth checking against mechanical property targets before it becomes standard practice on a given line.

Does additive masterbatch absorb moisture in storage?#

It depends entirely on what is inside: most additive concentrates are stable in a closed bag, but a desiccant masterbatch is deliberately hygroscopic, and one supplier advises using it within 16-24 hours of opening the bag. Our source library holds no general shelf-life or storage-condition data for additive masterbatch as a category; treat storage conditions as a question for the specific supplier's data sheet, the way phosphite antioxidant powders, which ship in aluminium-coated bags because of their own moisture sensitivity, already are.

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