Iron Oxide Pigments (Pigment Red 101, Yellow 42, Black 11): Properties, Uses in Plastics and Regulatory Status

Iron oxide pigments are 3 inorganic colorants used in plastics: red Pigment Red 101 (diiron trioxide, Fe2O3, CAS 1309-37-1), yellow Pigment Yellow 42 (iron hydroxide oxide, CAS 51274-00-1) and black Pigment Black 11 (triiron tetraoxide, CAS 1317-61-9), with browns made by blending them. Because each colour is a separately registered substance, the first question for a compounder is which of the three a data sheet actually describes, and the second is what the food-contact rules allow.

All three are REACH-registered (diiron trioxide at 100,000 to 1,000,000 t/y, PY42 and PBk11 at 10,000 to 100,000 t/y each), none is on the SVHC Candidate List, iron oxide holds EU food-contact entry FCM 409 with no specific migration limit but under the Annex II iron limit of 48 mg/kg of food, and 21 CFR 178.3297 lists iron oxides as colorants for polymers without a numeric limit. Iron oxides are one group of colorant pages in our database of plastic additives, each with the same identity, loading and regulatory fields.

This page covers the identity and colour of the three pigments, how they colour and hide, the measured properties of the red, the ECHA typical concentrations (5 wt% yellow, 1 wt% black) and the masterbatch route into wood-plastic composites, pipes and toys, the performance gaps, the silane, pro-oxidant and shrinkage questions, the dated regulatory matrix with the FCM 409 CAS question, the safety record, 5 competing pigments and the recorded producers.

The identity and headline regulatory fields of the three pigments are compared below, in the order red, yellow, black.

Table T1. Iron oxide pigment identity card.

Three pigments, three CAS numbers: the EU food-contact entry FCM 409 is written under a fourth, CAS 1332-37-2. Empty cells mean the value is not in our knowledge base; we do not estimate. Values as of 24 October 2026.

What Are Iron Oxide Pigments?#

Iron oxide pigments are inorganic pigments made of iron and oxygen (and, in the yellow, hydroxide) that colour a plastic red, yellow, brown or black while staying insoluble in the polymer melt. Their colour comes from Fe(III) charge-transfer absorption. Where do iron oxides sit among the colorants a compounder can choose? In the inorganic branch, the metal oxides, sulfides and aluminosilicates, beside titanium dioxide, carbon black, chromium oxide green and the ultramarines, as opposed to the organic pigments and the soluble dyes.

Insolubility separates a pigment from a dye: the pigment stays a particle and colours as a dispersed solid, while a dye dissolves in the melt. Iron oxides therefore belong to the insoluble, inorganic branch of colorants for plastics, which titanium dioxide (Pigment White 6) and carbon black (Pigment Black 7) lead by volume.

What pigment is PR101?#

PR101 is C.I. Pigment Red 101, the red iron oxide: diiron trioxide (Fe2O3, molecular weight 159.69 g/mol), registered under CAS 1309-37-1 and EC 215-168-2 and also sold as iron oxide red or hematite. "Pigment Red 101" is one of the Colour Index (C.I.) pigment names maintained by the Society of Dyers and Colourists and AATCC, a Generic Name built from class, hue and number. The C.I. constitution number that producer pages print for PR101 is not given here until it is verified.

Which iron oxide gives which colour: red, yellow, black or brown?#

Iron oxides give 4 colours from 3 pigments: red from Pigment Red 101 (Fe2O3), yellow from Pigment Yellow 42 (iron hydroxide oxide), black from Pigment Black 11 (triiron tetraoxide), and brown from blends of them. The answer to "what is the color of iron oxide?" therefore depends on which oxide is meant. The 4 iron oxide colours and their pigments are listed below.

• Red: C.I. Pigment Red 101, diiron trioxide (iron oxide red, hematite), Fe2O3, CAS 1309-37-1.
• Yellow: C.I. Pigment Yellow 42 (C.I. 77492), iron hydroxide oxide yellow, FeOOH by its ECHA name, CAS 51274-00-1.
• Black: C.I. Pigment Black 11 (C.I. 77499), triiron tetraoxide (black iron oxide), Fe3O4 by its ECHA name, CAS 1317-61-9.
• Brown: blends of the red, yellow and black oxides.

Brown is a blend, not a fourth C.I. iron oxide in our record, so a brown masterbatch carries the identities and regulatory files of the pigments it was mixed from.

Why do PY42 and PBk11 carry their own CAS numbers?#

PY42 and PBk11 carry their own CAS numbers because they are different iron compounds, iron hydroxide oxide and triiron tetraoxide, each registered separately under REACH, so a document that gives CAS 1309-37-1 for a yellow or black iron oxide is describing the red. The three separately registered substances also sit in different tonnage bands: diiron trioxide at 100,000 to 1,000,000 t/y, PY42 (EC 257-098-5) and PBk11 (EC 215-277-5) at 10,000 to 100,000 t/y each.

Three CAS numbers become four in food-contact law. Annex I of Regulation (EU) No 10/2011 names "iron oxide" as FCM 409 under CAS 1332-37-2, ECHA associates 1309-37-1 with that entry, and neither 51274-00-1 nor 1317-61-9 appears in Annex I (consolidated text of 14 July 2026). The practical reading is in the food-contact section below.

Is iron oxide a pigment or a filler in plastics?#

Iron oxide is a pigment first: its function in our record is to colour plastics red, yellow, brown or black, and it is the colour, not the mass, that a compounder pays for. The same oxides are also listed among the high-density fillers, because at about 5.2 g/cm3 they add mass and sound damping where a part needs weight. As colorants, the oxides are compared with titanium dioxide, chromium oxide green and the ultramarines under inorganic pigments for plastics; the filler role is covered below the contextual border.

How Do Iron Oxide Pigments Colour a Plastic?#

Iron oxide pigments colour a plastic by Fe(III) charge-transfer absorption, which removes part of the visible spectrum, and by scattering light at the particle surface, which hides the polymer behind the colour. Why are iron oxide parts opaque when organic-pigmented parts can be transparent? Hiding comes from scattering, which grows with the refractive-index difference between pigment and polymer and with particle size; organic pigments have a low refractive index and usually stay transparent, while inorganic pigments are opaque. In a 2023 polypropylene study in the International Journal of Molecular Sciences, a masterbatch built mostly on inorganic oxide pigments gave "opaque green products".

The 3 effects that make up iron oxide colouring are listed below.

• Charge-transfer absorption: the Fe(III) transition that sets the hue.
• Scattering: the particle-surface effect that gives opacity and hiding power.
• Insolubility: the property that keeps the pigment a particle, so it performs only once its agglomerates are dispersed.

An iron oxide colours fully only once those agglomerates are broken down and wetted, which is the job of dispersing agents for plastics and masterbatch. Our sources hold no particle size or refractive index for any iron oxide grade, so the mechanism carries no number here.

What Are the Physical and Chemical Properties of Iron Oxide Pigments?#

Pigment Red 101 is diiron trioxide, Fe2O3, with a molecular weight of 159.69 g/mol and a density of 5.24 to 5.25 g/cm3 (5,240 to 5,250 kg/m3), the only iron oxide in our record with measured physical values. The properties of the three pigments are compared below.

Table T2. Physical and chemical properties of iron oxide pigments.

Empty cells mean the value is not in our knowledge base; we do not estimate. Values as of 24 October 2026.

Our record holds no melting point, solubility value, oil absorption, particle size, refractive index or heat-stability value for any of the three pigments, and no molecular weight or density for PY42 and PBk11. Producer listings print heat figures per grade, but none is in our verified source set, so the cells stay empty: we publish only what our sources record.

Which Polymers Use Iron Oxide Pigments, and at What Loading?#

Iron oxide pigments are mapped by ECHA in 11 polymer groups, from polyolefins and PVC to polyamide and polycarbonate, at a typical concentration of 5 wt% for Pigment Yellow 42 and 1 wt% for Pigment Black 11. The ECHA plastic additives initiative mapping gives one typical concentration per substance for every polymer it lists, so these are reported use levels, not recommended dosages. How do they compare with colorant loadings generally? Colorants make up 0.01 to 5 wt% of plastic products (Hahladakis and colleagues, 2018, cited by Chea and colleagues, 2025), so the yellow sits at the top of the band, where opacity is bought with pigment mass. Our record holds no polymer-specific loading for PR101.

The ECHA typical concentrations for the three pigments are compared below.

Table T3. Iron oxide pigment loading in the ECHA mapping.

ECHA's mapping gives one typical concentration per substance, not a per-polymer recommendation.

Iron oxide pigments in polyolefins and PVC#

In polyolefins and in both rigid and flexible PVC, ECHA's mapping records Pigment Yellow 42 at a typical 5 wt% and Pigment Black 11 at 1 wt%, the same values it gives for every other polymer group. The pipes and wood-plastic composites in our application record are polyolefin and PVC articles. How pigments fit beside stabilizers, lubricants and fillers is set out in the guide to additives for PVC.

How does a PVC recipe written in phr translate into those percentages? Weight percent equals the phr of the ingredient divided by the total phr, multiplied by 100, with the pigment counted in the total: 100 phr PVC, 50 phr of other ingredients and 2 phr of iron oxide total 152 phr, so the pigment is 2 / 152 × 100 = 1.3 wt%.

Iron oxide pigments in engineering plastics and polyurethane#

ECHA's mapping places both PY42 and PBk11 in polyamide, polycarbonate, PET, PMMA, ABS, polystyrene and polyurethane, so iron oxides are not confined to the commodity polymers. Whether a given iron oxide grade survives a polyamide or polycarbonate melt is a grade question that our record cannot answer, so the supplier's heat-stability figure decides it; the performance section sets out what is recorded.

Iron oxide pigments in color masterbatch: loading and let-down ratio#

Iron oxide pigments reach most plastics as brown or red color masterbatch, a concentrate that typically carries 40 to 65 wt% pigment and is let down at 1 to 5 % of the base polymer. Brown and red iron oxide shades reach the converter as color masterbatch, a pigment concentrate in a carrier resin; both ranges are general masterbatch figures (15 to 80 wt% in extreme cases), not values specific to iron oxide.

How does the let-down set the pigment content of the part? The 3 steps of the calculation for a PY42 concentrate are listed below.

1. Multiply the masterbatch pigment content by the addition rate: 50 wt% PY42 added at 2 % gives 0.50 × 2 = 1.0 wt% PY42 in the part.
2. Express the addition as a ratio: 2 parts masterbatch to 98 parts natural polymer is 49:1.
3. Solve for the target: ECHA's typical 5 wt% PY42 from the same concentrate needs a 10 % addition, or 9:1.

In mass terms, 25 kg of masterbatch per tonne of polymer is a 2.5 % addition. Any other strength or target can be checked in both conventions with the let-down ratio calculator.

What Are Iron Oxide Pigments Used For? 3 Plastics Applications#

Iron oxide pigments are used in 3 plastics applications in our record, wood-plastic composites, plastic pipes and toys, and all three are usually coloured through brown or red masterbatch. Concrete, cosmetics and artists' paint also use iron oxides, but they sit outside this plastics reference. The 3 plastics applications are listed below.

• Wood-plastic composites: polyolefin and PVC matrices filled with wood.
• Plastic pipes: extruded pipe coloured through colour masterbatch.
• Toys: moulded articles where a pigment free of lead, cadmium and hexavalent chromium matters.

Wood-plastic composites#

Wood-plastic composites are one of the recorded outlets for iron oxide pigments, where the oxide colours a polyolefin or PVC matrix that carries wood fibre. Both matrix families sit in ECHA's mapping, with PY42 at a typical 5 wt% and PBk11 at 1 wt%. The pigment is one line in a package built around coupling agents, lubricants, UV stabilizers and biocides, the full package described under additives for wood-plastic composites.

Plastic pipes#

Plastic pipes are a recorded iron oxide application, coloured with colour masterbatch that Ampacet's pipe guidance lets down at 2 to 4 % (49:1 to 24:1) for pressure pipe and often less for non-pressure pipe. That figure covers colour masterbatch in pipe generally, not iron oxide specifically: a 50 wt% concentrate added at 2 to 4 % puts 1 to 2 wt% pigment into the pipe wall. Which pipe colour uses which iron oxide is not recorded. The stabilizer and colour package of each pipe type is covered under additives for plastic pipes.

Toys and childcare articles#

Toys are a recorded iron oxide application, and the reason is regulatory as much as aesthetic: iron oxides carry none of the lead, cadmium or hexavalent chromium that toy and packaging rules target. The EU Toy Safety Regulation (EU) 2025/2509 entered into force on 1 January 2026 and applies generally from 1 August 2030. Which additives toy rules allow and exclude is set out under additives in toys and childcare articles.

How Do Iron Oxide Pigments Perform? Heat, Light and Weathering#

Iron oxide pigments are recorded as UV-screening pigments alongside carbon black, rutile titanium dioxide and zinc oxide, but our sources hold no heat-stability, lightfastness or weathering value for PR101, PY42 or PBk11, so performance has to be read from each grade's data sheet.

How is pigment performance measured when a supplier does quote it? Colour change is measured after xenon-arc exposure to ISO 4892-2 (Method A, cycle 1: 102 minutes of light and 18 minutes of spray, 0.51 W/(m2·nm) at 340 nm, black-standard temperature 65 ± 3 °C) or ASTM G155-25, and read as a CIELAB colour difference to ASTM D2244-25. A supplier's lightfastness figure comes from such accelerated weathering tests, and it means little without its cycle and exposure time.

The performance record for iron oxide pigments is summarised below.

Table T4. What our record holds on iron oxide performance.

Empty cells mean our sources hold no value; we do not estimate. Values as of 24 October 2026.

How the pigment classes rank on heat and light is compared under pigment fastness in plastics.

Do iron oxide pigments protect plastic from UV light?#

Yes, as a class: iron oxides are listed with carbon black, rutile titanium dioxide and zinc oxide among the pigments that screen ultraviolet light by absorbing and scattering it at the surface and through the bulk of a part. UV screeners (pigments) are one of the UV stabilizer classes, next to UV absorbers and hindered amine light stabilizers.

The evidence stops at the class. No measured UV-protection value for any iron oxide grade is in our record, so a pigment screen does not replace the absorber and HALS package described under UV stabilizers for plastics without test data. Colour also changes the heat load: Ampacet gives white pigmented plastics a maximum outdoor surface temperature typically 10 to 15 °C (18 to 27 °F) lower than black ones.

How hot can an iron oxide pigment be processed?#

No single temperature applies: our sources record no heat-stability value for Pigment Red 101, Yellow 42 or Black 11, and heat stability is always specific to the polymer and the pigment concentration. What does a compounder use instead? The supplier's heat-stability figure for the target polymer and dwell time decides, and where the processing window exceeds it, the complex inorganic colour pigments (calcined mixed-metal oxides with rutile, spinel or hematite lattices) are the class built for the highest temperatures. That class includes two iron-bearing spinels in our record, nickel iron chromite black (PBk30) and zinc iron chromite brown (PBr33), so moving to a CICP does not always mean leaving iron chemistry.

How Do Iron Oxide Pigments Interact with Other Additives?#

Iron oxide pigments meet 3 other additive questions in a formulation: how well silane coupling agents bond to them, whether their iron promotes oxidation, and how they change shrinkage and colour matching in the finished part. Colorant migration is not one of them: as insoluble pigments, iron oxides are not the class that bleeds or blooms, because migration is driven by solubility in the polymer.

Silane coupling agents and surface treatment#

Silane coupling agents bond only slightly to iron oxides: in Gelest's ranking of substrates, iron oxides sit with talc and titanium dioxide in the "slight" group, below silica, glass and alumina and above calcium carbonate and carbon black. The full ranking runs in 4 tiers: excellent (silica, quartz, glass), good (alumina, aluminosilicates, selected metals), slight (talc, titanium dioxide, iron oxides) and poor (calcium carbonate, gypsum, barytes, graphite, carbon black). A silane-treated iron oxide therefore gains less coupling than silane-treated glass. Which substrates silane coupling agents bond to, and at what loading, is set out on the silane page.

Iron pigments and polyolefin oxidation: pigment or pro-oxidant?#

Iron is one of the 3 metals, with manganese and cobalt, used deliberately as a pro-oxidant in oxo-degradable plastics, a product class banned in the EU since 3 July 2021 under Article 5 of Directive (EU) 2019/904. Those pro-oxidants, iron stearate among them, are added to accelerate breakdown, while an iron oxide pigment is added for colour. Does the pigment speed up polyolefin oxidation? Our record holds no measurement either way, so antioxidant selection for an iron-pigmented part is checked by oven ageing rather than assumed. How iron, manganese and cobalt salts work as pro-oxidant additives is covered on the oxo-degradable page.

Shrinkage, warpage and metamerism in coloured parts#

Our record holds no warpage measurement for iron oxides, and the nearest evidence is class-level: in a 2023 study in the International Journal of Molecular Sciences, an opaque chromium and copper oxide masterbatch at 1 to 5 wt% raised the flow-direction shrinkage of injection-moulded polypropylene by 49.5 to 58.3 % relative to neat PP. A transparent phthalocyanine masterbatch raised it by 13.6 to 22.3 %. Those figures describe chromium and copper oxides, not iron oxides. Which pigment classes nucleate polyolefins is the subject of pigment-induced warpage.

Metamerism is the second effect: when an iron oxide red or yellow replaces a lead chromate or cadmium shade, the match can hold under one light source and fail under another, which Ampacet names as the issue to manage in every heavy-metal switch. A replacement is approved by color matching and metamerism checks under more than one light source.

What Is the Regulatory Status of Iron Oxide Pigments?#

Iron oxide pigments are REACH-registered and absent from the SVHC Candidate List, hold EU food-contact entry FCM 409 with no specific migration limit but an iron limit of 48 mg/kg of food, and are listed in 21 CFR 178.3297 without a numeric limit (status 24 October 2026). Colorants as a class sit outside the EU Union list, and iron oxide is one of only 7 colorant-type substances with their own FCM entries (carbon black, titanium dioxide, zinc sulphide, iron oxide, mica, OB-1 and BBOT). The status under each instrument is set out below.

Table T5. Iron oxide pigment regulatory matrix, as of 24 October 2026.

Three rows stay open on purpose: an absent CLP, Proposition 65 or TSCA record is not a negative finding, so those cells read "not recorded" until a primary source is verified. How these instruments fit together is mapped under plastic additive regulations.

Are iron oxide pigments REACH registered, and are they SVHCs?#

Yes, all three are registered under REACH, Regulation (EC) No 1907/2006: diiron trioxide (PR101) in the 100,000 to 1,000,000 tonnes-a-year band and PY42 and PBk11 in the 10,000 to 100,000 band each; and no, none of the three is on the SVHC Candidate List. ECHA CHEM showed no Candidate List entry for PY42 or PBk11 on 22 September 2026, and our record gives PR101 no Annex XIV or Annex XVII entry. Titanium dioxide and carbon black are both registered at 1,000,000 to 10,000,000 t/y, so PR101 sits one band below the two volume pigments. What a tonnage band means for a supplier is explained under REACH and plastic additives.

Are iron oxide pigments allowed in EU food-contact plastics?#

Yes: iron oxide is one of 7 colorant-type substances with its own entry on the EU Union list, FCM 409 in Annex I of Regulation (EU) No 10/2011, with no specific migration limit, while the iron that migrates from the finished article is capped at 48 mg/kg of food by Annex II. The entry, Ref 62240, authorises iron oxide as an additive, and the article must also meet the overall migration limit of 10 mg/dm2 (60 mg/kg for infant articles). Annex I, Annex II and the overall migration limit are explained on EU 10/2011.

Which iron oxides does the entry name? Annex I writes "iron oxide" under CAS 1332-37-2, ECHA associates PR101's 1309-37-1 with it, and the CAS numbers of PY42 and PBk11 do not appear. For a yellow or black grade, food-contact status is therefore confirmed with the supplier's declaration of compliance rather than assumed from the red. The FCM 409 CAS map is set out below.

Table T6. FCM 409 CAS map.

Checked against the consolidated text of 14 July 2026. Whether the FCM 409 entry extends to PY42 and PBk11 is a legal reading we have not verified; we state what Annex I lists.

Every other pigment in the same masterbatch is checked against Resolution AP(89)1 for colorants in food-contact plastics and national rules, because the Union list carries no entry for it.

Does the 48 mg/kg iron migration limit apply to every pigmented article?#

Yes: the Annex II iron limit of 48 mg/kg of food applies to every plastic food-contact article in the EU, whichever iron oxide coloured it and whether or not that pigment has its own FCM number. Iron's 48 mg/kg is the highest of the 10 numeric metal limits in Annex II, against 0.05 mg/kg for cobalt and 0.02 mg/kg for nickel, the metals in CICPs such as nickel antimony titanium yellow; arsenic, cadmium, chromium, lead and mercury must not be detectable. The metal limits sit alongside the substance limits in the table of specific migration limits (SML) of plastic additives.

Are iron oxide pigments FDA-compliant for food-contact polymers?#

Iron oxides are listed in 21 CFR 178.3297, the FDA regulation on colorants for polymers, without a numeric limit, so their use in food-contact polymers is bounded by good manufacturing practice and by the rule that no colour may migrate visibly into the food. The section (eCFR current to 18 September 2026) allows use not in excess of the amount reasonably required, and it names "iron oxides" generically, not by C.I. name or CAS number; "FDA-compliant" here means listed for the use, never individually approved.

Titanium dioxide, phthalocyanine blue and green, PV19 and the ultramarines share the no-limit status, while chromium oxide green is limited to 5 % and zinc sulfide to 10 % by weight of the polymer. Every listed colorant and its limit is tabulated under 21 CFR 178.3297: colorants for polymers.

Do the PPWR, RoHS and toy rules restrict iron oxide pigments?#

No: the EU packaging limit of 100 mg/kg for lead, cadmium, mercury and hexavalent chromium combined (Regulation (EU) 2025/40, Article 5(4), applying from 12 August 2026) and the RoHS substance list both leave iron out. RoHS Annex II (Delegated Directive (EU) 2015/863) limits cadmium to 0.01 % and lead, mercury, hexavalent chromium, PBB, PBDE, DEHP, BBP, DBP and DIBP to 0.1 % per homogeneous material. Article 5(4) is one of the provisions of the EU Packaging and Packaging Waste Regulation (PPWR) that reach into a packaging formulation.

The heavy-metal limits still reach the pigment through its impurities, so a buyer asks for the lead, cadmium and mercury content of a grade; in Japan the JCII prerequisite for food-contact colorants, as reported by Lanxess, is a maximum of 100 ppm lead, 50 ppm mercury and 100 ppm cadmium.

Toy rules name the metals of concern, not iron. The EU Toy Safety Regulation (EU) 2025/2509 entered into force on 1 January 2026 and applies generally from 1 August 2030.

Are Iron Oxide Pigments Safe? Health, Safety and Environmental Profile#

Iron oxide pigments carry none of the regulatory flags that removed lead chromate and cadmium pigments from EU plastics: none of the three is a Substance of Very High Concern, PR101 carries no REACH restriction or authorisation entry and is not a persistent organic pollutant, and iron oxide is authorised for food-contact plastics in the EU and listed for food-contact polymers in the US. The 3 parts of the iron oxide safety record are listed below.

• Classification: no CLP classification, harmonised or notified, is recorded in our sources for PR101, PY42 or PBk11.
• Listings: no SVHC entry for any of the three; no REACH Annex XIV or Annex XVII entry and no Stockholm Convention listing for PR101.
• Food contact: EU FCM 409 with the Annex II iron limit of 48 mg/kg, and the US listing of iron oxides in 21 CFR 178.3297 without a numeric limit.

Our sources hold no CLP classification, no Proposition 65 status and no TSCA record for these pigments, so we do not label them "non-hazardous"; the supplier's safety data sheet gives the classification of a specific grade, and with no occupational exposure limit or IARC evaluation recorded here, it is also the document for dust handling.

What Are the Alternatives to Iron Oxide Pigments?#

The 5 pigments that compete with iron oxides in plastics are carbon black for black, Pigment Red 254 for red, bismuth vanadate and nickel antimony titanium yellow for yellow, and, as the restricted legacy option, lead chromate. Food-contact status orders the comparison: iron oxide and carbon black hold their own EU FCM entries and US listings, while the organic and mixed-metal alternatives sit outside the Union list and carry a 1 % US limit or no US listing. The iron oxides and their 5 alternatives are compared below.

Table T7. Iron oxide pigments and their alternatives, status as of 24 October 2026.

Status values from our knowledge base; "not listed" cells mean the instrument does not name the substance. We do not rank shade, jetness or heat stability: no comparative values are in our sources.

Iron oxide black (PBk11) vs carbon black (PBk7)#

Carbon black is the reference black for plastics and a UV screen at the same time, and iron oxide black (Pigment Black 11) is the inorganic alternative our sources list first when a part should not be pigmented with carbon. Carbon black (CAS 1333-86-4) holds EU FCM 411 at a maximum of 2.5 % w/w of the polymer, while PBk11 sits at a typical 1 wt% in ECHA's mapping. Grades, loadings and food-contact limits of the reference black are on carbon black in plastics.

Recycling is why carbon-black-free blacks exist: carbon black absorbs near-infrared light, so carbon-black parts cannot be identified by NIR sorters. Our record names iron oxide black, copper chromite black (PBk28), NIR-detectable and IR-reflective blacks and perylene blacks as alternatives, but whether a PBk11 part sorts reliably is not verified in our sources. Which blacks a sorter can see is compared under NIR-sortable black colorants.

Iron oxide red (PR101) vs organic reds such as Pigment Red 254#

Iron oxide red and Pigment Red 254 solve different problems: PR101 is an opaque inorganic red with its own EU food-contact entry and no numeric US limit, while PR254 is an organic DPP red capped at 1 % in US food-contact polymers and outside the EU Union list. Organic pigments have a low refractive index, so PR254 can give a transparent red where PR101 hides the polymer. Pigment Red 254 (CAS 84632-65-5) is held to that 1 % ceiling under conditions of use B to H, and DPP pigments are reported to be stable to heat but not to acid and base (a secondary-source note). Our sources hold no shade or heat ranking between the two reds.

Iron oxide yellow (PY42) vs bismuth vanadate and nickel titanium yellow#

Iron oxide yellow is the yellow with the simplest food-contact file: PY42 shares the US "iron oxides" listing with no numeric limit and the Annex II iron limit of 48 mg/kg, while bismuth vanadate is not listed in 21 CFR 178.3297 and PY53 is capped at 1 % in the US and faces EU limits of 0.02 mg/kg for nickel and 0.04 mg/kg for antimony. Where do the alternatives win? Bismuth vanadate (Pigment Yellow 184, CAS 14059-33-7) is recorded as a bright yellow with high chroma and hiding power, the lead-free replacement for lead chromate yellows. Nickel antimony titanium yellow rutile (PY53, CAS 8007-18-9) is a CICP whose REACH registration route is still being verified. PY42's own Annex I position is the CAS question of Table T6, so this comparison rests on the iron limit and the US listing, not on FCM 409.

Iron oxides as replacements for lead chromate and cadmium pigments#

Iron oxides are part of the heavy-metal-free palette that replaced lead chromate and cadmium pigments, which left EU plastics through the Candidate List, REACH Annex XIV and Annex XVII entries 23 and 63, while iron appears in none of those restrictions. Lead chromate (CAS 7758-97-6), PY34 (CAS 1344-37-2) and PR104 (CAS 12656-85-8) entered the Candidate List on 13 January 2010 and Annex XIV as entries 10 to 12 (sunset 21 May 2015), and lead in PVC is limited to below 0.1 % from 29 November 2024 under entry 63 (Regulation (EU) 2023/923). The authorisation history of lead chromate explains why its yellows and reds left EU plastics.

The replacement is not one-for-one: iron oxides cover the earthy reds, yellows and browns, while the bright chrome yellows and cadmium reds go mainly to bismuth vanadate, CICPs such as PY53 and PBr24, Pigment Red 254 and high-performance organic yellows. The cadmium pigments fall under Annex XVII entry 23 (cadmium max 0.01 % by weight in listed plastics), and cadmium sulphide has been on the Candidate List since 16 December 2013.

Who Manufactures Iron Oxide Pigments? Grades and Suppliers#

Iron oxide pigments for plastics come from producers our directory records as Lanxess in Cologne, Germany, and Venator, and they are traded under grade names such as Ferroxon Yellow and TAROX Iron Oxide LL-100HP for PY42 and Bayoxide E 8611 and FerroTint Black Iron Oxide for PBk11. The trade names come from ECHA registration records and carry no recorded brand owner, so this page does not attribute them to a company, and no PR101 trade name is recorded yet. Producers by pigment class and region are listed in the directory of pigment manufacturers and suppliers for plastics.

The recorded producers and trade names are listed below, producers first, then trade names in the order red, yellow, black.

Table T8. Iron oxide pigment producers and trade names.

We list a company only where our knowledge base records it. Generic names in the ECHA trade-name field ("Iron Oxide Black", "ossido di ferro giallo") are omitted. No PR101 trade name is recorded yet; see our methodology.

Buyers should ask for the grade's CAS number, because a yellow or black sold as "iron oxide" may carry 51274-00-1 or 1317-61-9 rather than the 1309-37-1 of the red, and with it a different food-contact file.

How Do Iron Oxides Fit into the Wider Inorganic Pigment Family?#

Iron oxides are the coloured oxides of the inorganic pigment class, which titanium dioxide and carbon black lead by volume and which also holds chromium oxide green, zinc sulfide and the ultramarines. The volume leader, titanium dioxide (TiO2, Pigment White 6), holds EU FCM 610 with no specific migration limit, while chromium oxide green (Pigment Green 17, CAS 1308-38-9) is capped at 5 % in US food-contact polymers.

Iron also turns up in plastics in 4 other roles: as a coating on effect pigments, inside the lattice of mixed-metal pigments, as a high-density filler and, as iron powder, in oxygen scavengers. Each is a different additive with a different owner page.

Iron oxide in effect pigments and complex inorganic colour pigments#

Iron oxide is also the colouring layer on mica in pearlescent effect pigments, and iron is a lattice metal in two complex inorganic colour pigments in our record, nickel iron chromite black (PBk30) and zinc iron chromite brown (PBr33). Pearlescent and interference pigments are mica or synthetic substrates coated with titanium dioxide or iron oxide; mica holds EU FCM 597 with no specific migration limit. Coated mica platelets are the core of effect pigments (pearlescent, metallic).

PBk30 (CAS 71631-15-7) and PBr33 (CAS 68186-88-9) are recorded at a typical 5 wt% in ECHA's mapping and are not listed in Annex I of Regulation (EU) No 10/2011, so they do not share the FCM 409 entry. Iron-bearing spinels are two of the complex inorganic color pigments built for the highest processing temperatures.

Iron oxide as a high-density filler#

Iron oxide doubles as a high-density filler: the fillers record groups iron oxides, magnetite and hematite at about 5.2 g/cm3 with barium sulfate, tungsten and bismuth compounds among the fillers used to add mass, sound damping and a heavier feel. Our barium sulfate record also lists iron oxide among its alternatives. The density-raising group is one of the classes compared under fillers for plastics.

Iron-based oxygen scavengers are a different additive#

Iron-based oxygen scavengers use iron in the opposite direction: reduced iron powder (CAS 7439-89-6) in a film or closure turns into iron oxide as it consumes oxygen, so the oxide is the spent product, not the additive. The moisture-activated reaction uses a sodium chloride activator and needs about 65 % relative humidity, and 1 g of iron removes about 300 cm3 of oxygen at STP. Film and closure formats of iron-based oxygen scavengers are covered on their own page.

Iron oxide in concrete, cosmetics and artists' paint#

Iron oxide pigments are also sold to colour concrete, cosmetics and artists' paint, and those grades, specifications and safety rules are outside this reference, which covers iron oxide only as an additive in plastics. A concrete or cosmetic grade data sheet answers none of the plastics questions on this page.

What is the price of 1 kg of red oxide?#

Our sources record no price for iron oxide pigments, so we do not quote one: the price of a kilogram of red oxide depends on the grade and the order volume, and comparable quotes from more than one supplier are the only reliable figure. The request-for-quote block in the sourcing section collects those quotes against one specification, including the CAS number the price applies to.

Is red oxide harmful to humans?#

Red iron oxide carries none of the EU flags that mark a harmful plastics additive: PR101 is not a Substance of Very High Concern, has no REACH restriction or authorisation entry and is authorised for food-contact plastics as FCM 409. Our sources hold no CLP classification for it, so the grade's safety data sheet is the place to check dust and handling hazards; the safety section above sets out the full record.