Colorants for Plastics: 9 Types, Mechanisms, Dosage and Selection

Colorants for plastics are the pigments, dyes and optical brighteners added to a polymer to give it color, opacity or whiteness, and they make up between 0.01 and 5 wt% of a finished plastic product (Chea et al. 2025, adapted from Hahladakis et al. 2018). That range spans three orders of magnitude, from 5 ppm of a brightener in natural polyolefin film to 5 wt% of titanium dioxide in a white compound, which raises the practical question: which of the 9 types belongs in which polymer, and at what level?

A colorant decides five things at once: hue, which the organic pigments and solvent dyes deliver with the highest chroma; opacity, which titanium dioxide and the complex inorganic color pigments deliver and a dissolved dye cannot; the lightfastness and heat-stability ceiling, which the mixed metal oxides hold and the diarylide yellows lose above about 200 °C; food-contact status, since most organic pigments sit outside the EU Union list; and the side effects it brings, from warpage to migration and lost near-infrared sortability.

Colorants are one of the 43 families of plastic additives, and pigments alone fill 127 of the 418 rows of ECHA's plastic additives mapping, its largest single function tab. This page defines a colorant, separates pigment from dye, explains Colour Index naming and the three optical mechanisms, describes all 9 types, gives dosage in wt%, ppm and let-down ratio, matches class to polymer, sets out 7 selection criteria, the four failure modes, the test methods and the US, EU and REACH regimes, names the producers and lists all 68 colorant substances.

The table compares the 9 types of colorants for plastics by chemistry, loading, opacity, host polymers and named examples.

Loadings are typical use levels in the compound. FDA and EU percentages quoted elsewhere on this page are legal maxima for food contact, not recommendations.

What Are Colorants for Plastics?#

A colorant is a dye, pigment or other substance used to impart color to or alter the color of a plastic, and the US definition in 21 CFR 178.3297(a) expressly includes optical brighteners and fluorescent whiteners, which may not themselves be colored. The class therefore holds three optical behaviours rather than one: insoluble pigments that scatter and absorb, soluble dyes that only absorb, and brighteners that absorb invisible ultraviolet light and emit visible blue.

Which colored substances are therefore not colorants? Carbon black dosed for ultraviolet protection in a pressure pipe is the same substance in a different function, and laser-marking pigments, near-infrared reheat absorbers and fluorescent tracers are classed by what they do, not by the color they happen to have.

Pigment or dye: which one colors your polymer?#

A pigment stays as a solid particle in the polymer and colors it by absorbing and scattering light, while a dye dissolves molecularly in the melt and gives a transparent, brilliant color with no hiding power. A pigment particle has its own refractive index, so it can hide what lies behind it: inorganic pigments such as chromium oxide green and the copper chromite blacks give fully opaque compounds, while organic pigments sit close to the polymer in refractive index and stay transparent.

A dye has no particle and therefore no scattering, which is why it is used where the part has to stay clear. Lanxess lists its Macrolex solvent dyes for the predominantly amorphous thermoplastics, from polystyrene and ABS to polycarbonate, rigid PVC and PET. The same solubility makes a dye mobile, so it diffuses to the surface of a semi-crystalline polyolefin. The three practical differences are listed below.

• Solubility: a pigment stays a discrete insoluble particle; a dye dissolves molecularly in the melt.
• Optical effect: a pigment absorbs and scatters and can hide; a dye only absorbs and stays transparent.
• Migration: a pigment stays where the melt put it; a dye is mobile and migrates in polyolefins, which is why polyolefins are pigmented rather than dyed.

How colorants are named: the Colour Index#

Every colorant in plastics carries a Colour Index Generic Name such as C.I. Pigment Blue 15:3 and, for most classical pigments, a Constitution Number such as C.I. 74160, and the two identify the application class and the chemical structure respectively. Colour Index International lists more than 27,000 products under some 13,000 C.I. Generic Names, is maintained jointly by SDC Enterprises and the AATCC, was first printed in 1924 and has been online since the fourth edition of 2000.

The Generic Name states the class and the shade slot, so C.I. Pigment Blue 15 covers every copper phthalocyanine blue and the suffix separates the crystal forms 15:1 to 15:4. The Constitution Number states the chemistry: PB15 is C.I. 74160, CAS 147-14-8; phthalocyanine green PG7 is C.I. 74260, CAS 1328-53-6; quinacridone PV19 is C.I. 73900, CAS 1047-16-1; chromium oxide green PG17 is C.I. 77288, CAS 1308-38-9; and titanium dioxide PW6 is C.I. 77891, CAS 13463-67-7. How the two identifiers are built is explained on Colour Index (C.I.) pigment names.

Why colorants are not on the EU food-contact positive list#

Colorants sit outside the Union list of Regulation (EU) No 10/2011, because that list covers monomers and additives, so an organic pigment or a solvent dye carries no FCM number and no specific migration limit. The correct statement in a food-contact dossier is that the colorant is not on the Union list, and that national rules and Council of Europe Resolution AP(89)1 apply instead. The scope of the Union list is explained on EU 10/2011.

The 9 colorant-type entries that do carry FCM numbers are listed below.

• Carbon black: FCM 411, maximum 2.5 % w/w in the polymer.
• Titanium dioxide: FCM 610, no specific migration limit.
• Surface-treated titanium dioxide: FCM 805, FCM 873, FCM 1077.
• Zinc sulfide: FCM 403.
• Iron oxide: FCM 409.
• Mica: FCM 597.
• OB-1: FCM 422, SML 0.05 mg/kg.
• BBOT: FCM 500, SML 0.6 mg/kg.
• The methylated and unmethylated bis(benzoxazolyl)stilbene mixture: FCM 65, max 0.05 % w/w in the formulation.

Two further layers of Regulation (EU) No 10/2011 bind every colored article regardless of the Union list. Annex II caps migrating metals in mg/kg food at 1 for aluminium and barium, 0.05 for cobalt, 5 for copper and zinc, 48 for iron, 0.6 for lithium and manganese, 0.02 for nickel and 0.04 for antimony, with arsenic, cadmium (limit of detection 0.002), chromium, lead and mercury not detectable. The overall migration limit of 10 mg/dm2, or 60 mg/kg for articles intended for infants, applies on top.

Are pigments plastic additives?#

Yes: pigments are plastic additives, and they form the largest single group in ECHA's plastic additives mapping, with 127 of its 418 rows. ECHA built that mapping on the additive definition of Article 3(7) of Regulation (EU) No 10/2011 and then added pigments to it explicitly, which is why the mapping also carries their typical use concentrations: mostly 2 wt% for organic pigments, 5 wt% for complex inorganic color pigments and titanium dioxide, and 0.5 wt% for Prussian blue, ultramarine violet and copper chromite black.

How Do Colorants Work in a Polymer?#

Colorants work in 3 ways: a pigment particle absorbs part of the visible spectrum, a high-refractive-index particle also scatters light and so hides what is behind it, and a dissolved dye only absorbs, which is why it colors without hiding. The three mechanisms are not alternatives that a formulator picks between; they are the physics that decides whether a given colorant can deliver an opaque white, a transparent red or a colorless whitening effect in the polymer at hand.

Absorption, scattering and hiding power#

A pigment hides what is behind it by scattering light, and scattering rises with the difference in refractive index between the pigment and the polymer, which is why titanium dioxide is the reference white in plastics at an optimal crystal size of about 220 nm. Particle size matters as much as refractive index, because scattering peaks when the particle diameter is of the same order as the wavelength being scattered.

Scattering has consequences beyond appearance. A white part reflects most of the solar spectrum, so its maximum outdoor surface temperature runs typically 10 to 15 °C below that of a black part, a difference Ampacet reports for weathered polyolefins. Absorption has the opposite effect and a useful one: carbon black absorbs the ultraviolet radiation that would otherwise degrade polypropylene, so a black compound is also a stabilized compound, and it absorbs near-infrared radiation as well, which removes a black part from the reach of a sorting line.

Why organic pigments are transparent and inorganic pigments are opaque#

Organic pigments have a refractive index close to that of the polymer, so they color without hiding: in a 2023 study in the International Journal of Molecular Sciences, a phthalocyanine masterbatch gave transparent green polypropylene while a chromium and copper oxide masterbatch at the same loading gave an opaque green. Both masterbatches were dosed over the same 1 to 5 wt% range into the same polypropylene, so the difference in appearance came from the pigment chemistry rather than from the level.

Transparency makes organic pigments the class of choice for tinted transparent parts and for deep, clean shades that an oxide cannot reach. The commercial weight follows: phthalocyanines account for about 25 % of all synthetic organic pigments, and about 25 % of the roughly 250,000 t of organic pigment produced in 2006 were diarylide yellows.

Dispersion: a pigment only performs once its agglomerates are broken down#

A pigment reaches its full color strength only when its agglomerates are broken down in the melt, because undispersed agglomerates scatter as specks instead of coloring, and finer particles are harder to disperse than coarse ones. Carbon black shows the structure clearly: primary particles fuse into aggregates, which the industry calls structure, and those aggregates associate loosely into agglomerates that shear has to pull apart again.

Particle size sets the difficulty. Ampacet specifies N550 at 40 to 48 nm as sufficient for pipe and moves to N330 at 26 to 30 nm or N110 below 20 nm for outdoor exposure longer than 3 to 5 years, while noting that finer particles are harder to disperse; that is North American practice under ASTM D3350, which sets no particle size, whereas ISO 4427-1 requires 10 to 25 nm, a band only an N110-type black meets. Dispersion quality is therefore measured rather than assumed: black masterbatch is rated on a microdispersion scale of 1 to 5, with 1 the best, on about 1.5 mil polyethylene film and reported per production lot. Split-feed production carries the rest, feeding the pigment through a twin-screw side feeder downstream of the melting zone so that it meets an already molten polymer and is wetted gently. Screw configurations and side-feeder positions are set out on plastic compounding.

9 Types of Colorants for Plastics#

The 9 types of colorants for plastics are inorganic pigments, complex inorganic color pigments, azo pigments, polycyclic high-performance pigments, solvent dyes, effect pigments, fluorescent pigments, photoluminescent pigments and optical brighteners. The order runs from the insoluble inorganic lattices through the insoluble organic chromophores to the soluble dyes, then through the three special-effect classes, and ends with the colorless brightener. Every table, list and diagram on this page keeps that same order.

1. Inorganic pigments: titanium dioxide, carbon black, iron oxides and ultramarine#

Inorganic pigments are metal oxides, sulfides and aluminosilicates that color and hide at the same time, and the two largest by volume in plastics are titanium dioxide (C.I. Pigment White 6) and carbon black (C.I. Pigment Black 7). Titanium dioxide, CAS 13463-67-7, comes in rutile and anatase forms and is the reference white; carbon black, CAS 1333-86-4, is the reference black and doubles as an ultraviolet screen. The colored oxides follow: iron oxides cover red as PR101, yellow as PY42 and black as PBk11, chromium oxide green is PG17, zinc sulfide is PW7, and ultramarine blue is PB29, a sulfur-bearing sodium aluminosilicate fired at 700 to 750 °C under reducing conditions.

Loadings sit at the top of the colorant range, because opacity costs mass: ECHA's mapping gives 5 wt% for titanium dioxide and 0.5 wt% for copper chromite black, and a black pressure pipe carries 2.0 to 2.5 wt% carbon black. Food-contact status is the most settled of all 9 types: titanium dioxide is FCM 610 with no specific migration limit, carbon black is FCM 411 at a maximum of 2.5 % w/w in the polymer, iron oxides are FCM 409 under the Annex II iron limit of 48 mg/kg, chromium oxide green is capped at 5 % by weight of the polymer and zinc sulfide at 10 %, and titanium dioxide, the iron oxides and the ultramarines carry no numeric US limit. The oxides are compared grade by grade on inorganic pigments for plastics.

2. Complex inorganic color pigments (CICP, mixed metal oxides)#

Complex inorganic color pigments are calcined mixed metal oxides in which coloring metals sit inside a rutile, spinel or hematite lattice, which is why they survive the highest processing temperatures and outdoor exposure better than any organic class. The range is narrow in shade and wide in performance: nickel antimony titanium yellow rutile PY53 (8007-18-9), chrome antimony titanium buff rutile PBr24 (68186-90-3), cobalt aluminate blue spinel PB28 (1345-16-0), copper chromite black spinel PBk28 (68186-91-4), nickel iron chromite black PBk30, zinc iron chromite brown PBr33, cobalt chromite blue-green PB36 and manganese antimony titanium buff PY164, all at an ECHA typical concentration of 5 wt%.

Regulatory treatment follows the metals rather than the lattice. The FDA caps PY53 and PBr24 at 1 % by weight under conditions B through H, PBk28 at 5 % under A through H and cobalt aluminate at 5 % in other polymers, all legal maxima rather than dose recommendations, while the EU Annex II limits bite hardest here, at 0.04 mg/kg antimony, 0.02 mg/kg nickel and 0.05 mg/kg cobalt with chromium not detectable. PY53 also falls under the nickel group of REACH Annex XVII entry 27. Shepherd Color sells a second CICP family for its infrared behaviour, where infrared-reflective grades reduce heat build-up warping in PVC profiles and an infrared black leaves black plastic sortable. The rutile and spinel grades are listed on complex inorganic color pigments.

3. Azo pigments: monoazo, diarylide, benzimidazolone and lakes#

Azo pigments are the largest and cheapest organic colorant class, built on one or two azo groups, and they run from the transparent monoazo yellow C.I. Pigment Yellow 74 through the diarylide yellows to the benzimidazolones and the calcium and barium lakes. The subclasses split by coupling chemistry: monoazo yellow PY74 (CAS 6358-31-2); the diarylide yellows PY12 (6358-85-6), PY13 (5102-83-0), PY14 (5468-75-7), PY17 (4531-49-1) and PY83 (5567-15-7); pyrazolone orange PO13 (3520-72-7); the benzimidazolones PY151, PY154, PO36, PO64 and PR176; the disazo condensation pigments PY93, PY95 and PR166; the lakes PR48:2, PR53:1 and PR57:1 (5281-04-9) with PY168 and PY183; and the nickel azo-barbiturate melamine complex PY150 (68511-62-6).

Heat is this class's ceiling, and the diarylides define it. Diarylide pigments decompose into monoazo species above about 200 °C, with a first thermogravimetric decomposition peak at 162 °C, and are reported to release 3,3'-dichlorobenzidine above 200 °C, so they are not specified above that temperature. In US food contact the class is thinly listed: 21 CFR 178.3297 allows PY180 (77804-81-0) at a maximum of 1.0 % by weight under conditions B through G, while PY83, PR122, PV23, bismuth vanadate, Solvent Red 135 and Solvent Yellow 114 are not listed at all. Azo and polycyclic classes are compared on organic pigments for plastics.

4. Polycyclic high-performance pigments: phthalocyanine, quinacridone, DPP and perylene#

Polycyclic high-performance pigments are fused-ring organic pigments, led by the phthalocyanines, quinacridones, diketopyrrolopyrroles and perylenes, and they are the classes that survive the melt temperatures of engineering plastics. Copper phthalocyanine blue is PB15 (147-14-8), in the alpha forms PB15, 15:1 and 15:2 and the more stable beta forms 15:3 and 15:4; phthalocyanine green is PG7 (1328-53-6) and the brominated chlorinated green PG36 (14302-13-7). Quinacridone is PV19 (1047-16-1), whose shade depends on the crystal form and whose melting point is 390 °C, with PR122 (980-26-7) and PR202 (3089-17-6) beside it. The diketopyrrolopyrrole reds are PR254 (84632-65-5), PR264 and PO73; the perylenes PR149, PR178, PR179 (5521-31-3) and PV29 (81-33-4); and dioxazine violet PV23 (6358-30-1), quinophthalone PY138 (30125-47-4), the isoindolines PY139 and PY185 and indanthrone PB60 (81-77-6) complete the range.

Chemistry sets two cautions. Diketopyrrolopyrrole pigments have high stability to heat but not to acid and base, and the early alpha-form copper phthalocyanines flocculated with rutile titanium dioxide, which is why the beta forms took over in white-reduced shades; ECHA CHEM shows PG36 as ceased manufacture under CAS 14302-13-7. In food contact, 21 CFR 178.3297 gives phthalocyanine blue, phthalocyanine green and quinacridone PV19 no numeric limit, and caps PR254, PR179 and PV29 at 1 % under conditions B through H, PR202 at 1.0 %, and PY138 at 1 % under C through H for articles not filled above 158 °F (70 °C). This class shares a family page with the azo pigments on organic pigments for plastics.

5. Solvent dyes#

Solvent dyes are polymer-soluble colorants that dissolve molecularly in the melt and give transparent, brilliant color with no hiding power, which is why they are used almost only in amorphous thermoplastics such as polystyrene, ABS, PMMA, polycarbonate and PET. The named chemistries are the perinone Solvent Red 135 (20749-68-2), the quinophthalone Solvent Yellow 114 (7576-65-0), the anthraquinones Solvent Violet 13 (81-48-1) and Solvent Blue 97 (32724-62-2), and the azine mixture nigrosine, Solvent Black 7 (8005-02-5).

Food-contact status has to be read supplier by supplier, because the class is barely present in the positive list. Lanxess states that nearly all Macrolex dyes are approved for coloring PET under FDA regulations at loadings below 0.20 %, and that all meet the AP(89)1 purity requirements. The only numeric solvent-dye entry in 21 CFR 178.3297 is Solvent Blue 104 (116-75-6) at a maximum of 0.0004 % by weight of PET complying with 177.1630; Solvent Red 135, Solvent Yellow 114, Solvent Violet 13 and nigrosine are not listed there, and clearance through another route is not verified. Nigrosine is also reported to decrease the crystallization rate of PA66. Grade-by-polymer suitability is on solvent dyes for plastics.

6. Effect pigments: metallic and pearlescent#

Effect pigments are platelet-shaped colorants that make the color change with the viewing angle: aluminium flakes reflect like tiny mirrors, and mica coated with titanium dioxide or iron oxide creates the pearlescent and interference shades used in caps, closures and cosmetic packaging. The effect comes from geometry rather than chromophore chemistry, because a platelet reflects at two parallel surfaces and the interference between the reflections produces the shift.

Two regulatory facts attach to the substrates. Mica is EU FCM 597 with no specific migration limit and is listed by the FDA as aluminum and potassium silicate (mica), and aluminium, the metal of the metallic flakes, carries an Annex II specific migration limit of 1 mg/kg. No typical loading or flake-orientation rule for this class is established, so none is stated here. Pearlescent and metallic systems are covered on effect pigments.

7. Fluorescent pigments#

Fluorescent pigments are fluorescent dyes dissolved in a resin carrier and ground to a powder, so they convert part of the ultraviolet and short-wavelength light into visible light and appear brighter than an ordinary pigment of the same hue. The carrier resin is what makes the dye behave as a pigment, since the dye alone would dissolve and migrate. That construction sets the class limitation: heat and light stability depend on the carrier and the dye rather than on a robust lattice, so a daylight-fluorescent color is a short-life color.

Fluorescent colorants used as markers belong elsewhere, because fluorescent and spectroscopic markers for tracer-based sorting and anti-counterfeiting are classed by function. No dosage, heat-stability figure or named grade for daylight-fluorescent pigments is established. Heat and light limits are covered on fluorescent pigments for plastics.

8. Photoluminescent (glow-in-the-dark) pigments#

Photoluminescent pigments store incident light and release it slowly after the light source is removed, which is how glow-in-the-dark safety signage, switches and exit markings are molded rather than printed. The mechanism is phosphorescence rather than fluorescence: the excited state is long-lived, so emission continues in the dark, and doped strontium aluminate is the chemistry named for this class.

Afterglow duration, loading and a CAS number for the strontium aluminate grades are not established, so no values are given here. Afterglow systems are covered on photoluminescent pigments.

9. Optical brighteners#

Optical brighteners are colorless fluorescent compounds that absorb ultraviolet light between 340 and 370 nm and re-emit blue light between 420 and 470 nm, so they mask the yellow cast of a natural polymer instead of coloring it. About 400 types are listed in the Colour Index and fewer than 90 are produced commercially. The two that dominate plastics are OB-1, CAS 1533-45-5, a bis(benzoxazolyl)stilbene melting above 359 °C, and BBOT, sold as optical brightener OB, CAS 7128-64-5, a bis(benzoxazolyl)thiophene melting at 192 to 208 °C.

Levels are set in ppm rather than in percent. Mayzo gives 5 to 10 ppm (0.0005 to 0.001 %) for BBOT in unpigmented polyolefins and 50 to 1,000 ppm in other substrates, 50 to 1,000 ppm (0.005 to 0.1 %) for OB-1 in polyester and polyamide fibres and in polycarbonate and polyester engineering plastics, and 50 to 2,000 ppm for the stilbene-biphenyl brightener CAS 40470-68-6, which is for indoor use only and is not FDA-cleared for food contact. A brightener loading has to rise when a UV absorber is present, because the absorber competes for the same ultraviolet light. Both leading grades are on the EU positive list, OB-1 as FCM 422 at 0.05 mg/kg with a note that the limit may be exceeded in fatty food simulants, and BBOT as FCM 500 at 0.6 mg/kg; in the US, OB-1 is capped at 0.025 % by weight and BBOT at 0.015 % under conditions A through H. Grade selection is on optical brighteners for plastics.

How Much Colorant Does a Plastic Need? wt%, ppm and Let-Down Ratio#

A colorant makes up between 0.01 and 5 wt% of a finished plastic product, and the level is set by opacity rather than by hue: a transparent organic pigment works at about 2 wt%, titanium dioxide and complex inorganic pigments at about 5 wt%, and an optical brightener at 5 to 10 ppm. Chea et al. 2025, adapting Hahladakis et al. 2018, give the 0.01 to 5 wt% band, and ECHA's mapping supplies the per-class values inside it.

The table gives the typical concentration of each colorant class in the compound.

Colorants rarely reach the machine as powder. They reach it as masterbatch, a concentrate carrying 40 to 65 wt% active content, 15 to 80 wt% in extreme cases, let down at 1 to 5 % of the base polymer. Both conventions have to be read together, because the industry writes the same dose two ways in one sentence. The North American standard black concentrate for pressure pipe carries 35 % carbon black and is let down at 5 to 6.5 %, which is 19:1 to 14:1, giving about 1.75 to 2.28 % carbon black in the pipe wall, below the 2.0 to 2.5 % that ISO 4427-1 requires over most of that range, which needs 5.7 to 7.1 %; concentrates above 40 % are avoided; colored pressure-pipe concentrate is let down at 2 to 4 %, which is 49:1 to 24:1; and 25 kg per tonne is the same statement as 2.5 %.

The table sets out the masterbatch and let-down practice behind those numbers.

Every level needs its base stated, because 2 wt% of the compound, 2 % of the blend and 2 % of the concentrate are three different quantities, and a regulatory percentage is a fourth. Any color dose can be checked in both conventions with the let-down ratio calculator.

Which Colorant for Which Polymer?#

The polymer decides the colorant three times over: its melt temperature rules out every class that degrades below it, its crystallinity decides whether a pigment will distort the part, and its transparency decides whether a dye is an option at all. Those three gates explain almost every entry in a colorant selection chart. Every polymer has a guide under additives by polymer.

The table pairs the major thermoplastics with the colorant classes that work in them, the classes to watch, and one sourced value each.

Colorants for polyethylene and polypropylene#

Polyethylene and polypropylene take pigments, not dyes, because a dye dissolved in a semi-crystalline polyolefin migrates to the surface, and the reference case is black pressure pipe, which carries 2.0 to 2.5 wt% carbon black with a primary particle size of 10 to 25 nm under EN 12201-1 and ISO 4427-1. The same compound has to hold an oxidation induction time of at least 20 minutes at 210 °C, which shows how tightly colorant and stabilizer package are specified together.

Ultraviolet absorption is the second job that black does. Two further effects apply: a pigment particle can nucleate the crystallizing polymer and change shrinkage in an injection-molded part, and an optical brightener is used at only 5 to 10 ppm in unpigmented polyolefins, where it masks the natural yellow cast rather than adding a color.

Colorants for PVC#

PVC is the one commodity polymer that takes both pigments and solvent dyes, because rigid PVC is amorphous, and its colorant problem is heat rather than migration: a dark profile in the sun builds up heat that distorts it. Lanxess lists rigid PVC among the Macrolex substrates.

Heat build-up drives colorant choice in siding and window profiles, and Shepherd Color states that infrared-reflective inorganic pigments reduce the warping and twisting it causes. Two further constraints apply: ultramarine blue is bleached by mineral acids with release of hydrogen sulfide, and lead in PVC articles is restricted to below 0.1 % w/w from 29 November 2024 under REACH Annex XVII entry 63, introduced by Regulation (EU) 2023/923, with recovered rigid PVC allowed up to 1.5 % until 28 May 2033.

Colorants for amorphous engineering plastics: PS, ABS, PC, PMMA and PET#

Amorphous engineering plastics are the home of the solvent dye: polystyrene, SAN, ABS, PMMA, polycarbonate, rigid PVC and PET dissolve the dye molecularly and keep it transparent, which no pigment can do. Lanxess lists that set for the Macrolex range, with EPS, styrene-butadiene, PPO and PBT.

Food-contact clearance here is dye-specific and numeric. Lanxess states that nearly all Macrolex dyes are approved for coloring PET under FDA regulations at loadings below 0.20 %, while the FDA's own entries cap Solvent Blue 104 at 0.0004 % by weight of PET complying with 177.1630 and the anthraquinone triazine CAS 4118-16-5 at 0.25 % in PET under conditions E through G. Where pigments are used instead, PR254, PR179 and PV29 are capped at 1 % under B through H, PR202 at 1.0 % and PY138 at 1 % under C through H. Each percentage is a legal maximum, not a formulation target.

Colorants for polyamides and high-temperature polymers#

Polyamide is the hardest polymer to color: its melt is hot and chemically reducing, so most dyes and many organic pigments do not survive it, and the classes that do are the complex inorganic pigments, the high-performance polycyclics and a small group of high-temperature dyes. Lanxess launched Macrolex Orange HT specifically to give a brilliant orange in polyamide, which states directly how few dyes reach that melt.

Black in polyamide has its own classical answer. Nigrosine, Solvent Black 7, is the traditional black for PA66 including glass-fibre-reinforced grades, and it is reported to decrease the crystallization rate, so it moves the processing window as well as the color. On the pigment side, the calcined mixed metal oxides survive the highest processing temperatures of any class, and the diketopyrrolopyrrole reds bring high heat stability although they are not stable to acid and base.

How Do You Select a Colorant for Plastics? 7 Criteria#

Select a colorant for plastics in 7 steps: fix the color and opacity target, take the polymer and its processing temperature, decide pigment or dye, define the service environment, screen the regulations for each market, check what the colorant does to the rest of the compound, then set the loading and confirm it by test. Each step removes candidates that the next would otherwise have to test. The 7 criteria are listed below.

1. Fix the color and opacity target, since opacity decides the class before hue decides the grade.
2. Take the processing temperature and strike out every class that degrades below it: diarylide yellows go first, above about 200 °C, only a few titanium dioxide grades suit extrusion above 525 °F (274 °C), and treated weathering grades are poor above 450 °F (232 °C).
3. Decide pigment or dye from crystallinity, because a solvent dye works only in an amorphous thermoplastic.
4. Check the service environment, since acids bleach ultramarine, acid and base attack the diketopyrrolopyrroles, and dark parts build up heat outdoors.
5. Screen the regulatory status for every market before sampling: food contact, toys, electrical goods, packaging.
6. Check what the colorant does to the compound: nucleation and warpage, interaction with the antioxidant package, and sortability, where APR Design Guide clause SORT-S-01 fails any color with L* below 40 or a near-infrared reflectance of 10 % or less.
7. Set the loading, compare cost-in-use by tinting strength rather than by price per kilogram, and confirm with a dispersion rating and a color measurement.

A pigment with twice the tinting strength at twice the price is cost-neutral on paper and cheaper in practice, because it occupies less of the compound.

Which additives conflict with a colorant?#

Colorants interact with the rest of the additive package in four known ways, and three of them show up as a color defect rather than as a mechanical failure. The conflicts are listed below.

• Phenolic antioxidants and low-treated titanium dioxide: over-oxidation of the phenol to a quinone turns white polyethylene and polypropylene pink. The phenolic grades are compared on antioxidants for plastics.
• UV absorbers and optical brighteners: the absorber competes for the ultraviolet light the brightener needs, so the brightener loading has to rise.
• Pigments and nucleating agents: a pigment that nucleates a semi-crystalline polymer changes shrinkage and can work against a nucleating agent added for cycle time.
• Titanium dioxide and alpha-form copper phthalocyanine: the alpha forms flocculated with rutile titanium dioxide, which is why beta-form PB15:3 and PB15:4 dominate white-reduced blues.

Some UV stabilizers add a further path, because a high pH aggravates pinking alongside nitrogen oxide gas fading, moisture and storage in the dark, and zinc stearate is the classical remedy in the same mechanism.

What Goes Wrong with Colored Plastics?#

Four things go wrong with a colored plastic: the pigment does not survive the process or the sunlight, it nucleates the polymer and warps the part, it leaves the polymer and stains what it touches, or the white compound turns pink in the warehouse. Each failure has a different owner in the formulation, and each is diagnosed by a different test, which is why they are treated separately below.

Heat stability and lightfastness limits#

Heat stability is polymer-specific and concentration-specific, and the first class to fail is the diarylide yellows, which decompose into monoazo species above about 200 °C. That decomposition has a measurable onset, with a first thermogravimetric peak at 162 °C, and it is reported to release 3,3'-dichlorobenzidine above 200 °C, so 200 °C is a degradation onset rather than a melting point.

The white pigment has its own thermal window. Only a few titanium dioxide grades suit extrusion above 525 °F (274 °C), and highly treated weathering grades are poor candidates above 450 °F (232 °C). Chemical resistance sits beside heat resistance: diketopyrrolopyrrole pigments are stable to heat but not to acid and base, and ultramarine is bleached by mineral acids. At the top of the scale the complex inorganic color pigments are the heat and weather reference. Class-by-class fastness data are on pigment fastness in plastics.

Pigment-induced warpage in HDPE, PP and polyamides#

A pigment particle can act as a nucleating agent, and in a semi-crystalline polymer that changes shrinkage: in a 2023 study on injection-molded polypropylene published in the International Journal of Molecular Sciences, the relative shrinkage in the flow direction rose from 13.6 % to 22.3 % as a transparent phthalocyanine masterbatch went from 1 to 5 wt%. The same study measured the opaque comparison in parallel, where a chromium and copper oxide masterbatch raised flow-direction shrinkage from 49.5 % to 58.3 % over the identical range.

Nucleating strength differs between chemistries that look interchangeable on a shade card, and phthalocyanines nucleate polypropylene slightly more efficiently than quinacridones. A second, unrelated mechanism operates in dark exterior PVC, where absorbed heat distorts the profile and infrared-reflective pigments address the thermal case rather than the crystallization case. Both are set out on pigment-induced warpage.

Colorant migration: bleeding, blooming and plate-out#

Colorant migration has three faces: bleeding into a material in contact, blooming to the surface, and plate-out on the tool, and all three are driven by how soluble the colorant is in the polymer. A dissolved dye is mobile by definition, which is why the same dye that performs perfectly in polystyrene bleeds out of polyethylene. Bleeding, blooming and plate-out are covered together on colorant migration in plastics.

Migration is also what the food-contact rules measure. Regulation (EU) No 10/2011 caps overall migration at 10 mg/dm2, or 60 mg/kg for articles intended for infants, and its Annex II metal limits apply whether or not the pigment is on the Union list. The brightener OB-1 shows how tight a limit can be, since its FCM 422 entry carries 0.05 mg/kg with a note recording the risk that it could be exceeded in fatty food simulants.

Solubility and diffusion are the two variables a formulator can act on, and the diffusion models are on additive migration.

Pinking and yellowing of white polyolefins#

White polyethylene and polypropylene turn pink in storage when the phenolic antioxidant in the compound is over-oxidised to a quinone, and a low-treated rutile titanium dioxide, nitrogen oxide gas fading, moisture and darkness all make it worse. A high pH from some UV stabilizers is a further aggravating condition, which makes the defect a formulation problem rather than a pigment problem.

The remedy sits in the same mechanism. Zinc stearate forms colorless zinc-quinone complexes with the oxidised phenol, and grade selection carries the rest, since the low surface-treatment rutile that suits high extrusion temperatures is the grade that promotes pinking.

Metamerism is a shade problem of a different kind: two colors match under one illuminant and fail under another, and it has to be managed deliberately when a heavy-metal pigment is replaced, because the replacement rarely has the same spectral curve. The full set of mechanisms is on why plastics turn yellow or pink.

How Is Color Measured and Colorant Performance Tested?#

Color in plastics is measured in the CIELAB L*a*b* space that the CIE defined in 1976, and the two numbers that decide a production release are the color difference from the standard and, for white and natural compounds, the yellowness index measured to ASTM E313. The older CIE Yxy space of 1931, built on the tristimulus XYZ values, is still quoted in instrument software and older specifications.

Standard editions matter as much as method names, because a withdrawn standard invalidates a test report. Yellowness index is ASTM E313-20, reapproved in 2025; ASTM D1925 was withdrawn in 1995 and is never cited as current; color difference is ASTM D2244-25. Tolerances and illuminants are on color measurement and matching of plastics.

The table lists what is tested on a colored compound, the method, the current reference and the decision each test supports.

How Are Colorants Regulated?#

Colorants for plastics are regulated in 4 layers: a US food-contact positive list in 21 CFR 178.3297, an EU regime that leaves colorants outside the Union list and hands them to national rules and Council of Europe Resolution AP(89)1, REACH authorisation and restriction for the heavy-metal pigments, and packaging and product rules such as the PPWR metal cap. A fifth layer applies to exporters into Japan, where the JCII sets a prerequisite of at most 100 ppm lead, 50 ppm mercury and 100 ppm cadmium for food-contact colorants, its Food Contact Materials Safety Center having taken over JHOSPA certification from 1 April 2021. Every instrument is summarised in plastic additive regulations.

The table is the cross-regime matrix for 31 colorants: the US numeric position, the EU position, the REACH status and the note that changes a sourcing decision.

Percentages under 21 CFR 178.3297 are legal maxima for food-contact use, not recommended dosages. "Not on the Union list" means the colorant falls outside Regulation (EU) No 10/2011; national rules and Resolution AP(89)1 apply.

Food contact: 21 CFR 178.3297, EU 10/2011 and Resolution AP(89)1#

In the United States a colorant for a food-contact plastic must appear in 21 CFR 178.3297 or be cleared by another route, and the section lists some colorants without a numeric limit and others with a cap such as 1 % by weight of the polymer under conditions of use B through H. Every entry also carries a general condition: the colorant must be used in accordance with good manufacturing practice, at levels not in excess of those reasonably required for the technical effect. Colour additives listed in 21 CFR parts 73, 74, 81 and 82 for direct use in food, and their lakes, may be used as polymer colorants as well. The full list is on 21 CFR 178.3297.

Where a colorant is absent, the correct statement is that it is not listed and that clearance through a Food Contact Notification or another route is not verified: that applies to PY83, bismuth vanadate, Solvent Red 135, Solvent Yellow 114, PR122, PV23, Solvent Violet 13 and nigrosine. No colorant is an approved product in US law, because the agency lists substances for uses rather than approving products.

The EU takes the opposite architecture. Colorants are outside the Union list, so most pigments and every solvent dye carry no FCM number and no specific migration limit, and compliance is demonstrated against national rules and Council of Europe Resolution AP(89)1, which sets purity requirements for colorants in food-contact materials. Three provisions still bind every colored article: the Annex II metal limits, the overall migration limit, and Article 9(2), under which a nanoform may be used only when explicitly authorised in Annex I. The purity framework is explained on Resolution AP(89)1.

Restricted colorants: lead chromate, cadmium and the PPWR metal limit#

The most restricted colorants in plastics are the lead chromates and the cadmium pigments: lead chromate, C.I. Pigment Yellow 34 and C.I. Pigment Red 104 have been on the REACH Candidate List since 13 January 2010 and on the Authorisation List as Annex XIV entries 10 to 12, with a sunset date of 21 May 2015. The listing grounds are carcinogenicity under Article 57(a) and toxicity for reproduction under Article 57(c). Every listed colorant appears on the SVHC Candidate List.

The five landmark restrictions that shape a colorant specification today are listed below.

• Lead chromate pigments: Candidate List since 13 January 2010, Annex XIV entries 10 to 12, sunset date 21 May 2015.
• Lead in PVC: below 0.1 % w/w from 29 November 2024 under Annex XVII entry 63 (Reg. (EU) 2023/923), with recovered rigid PVC up to 1.5 % until 28 May 2033.
• Cadmium pigments: cadmium sulfide on the Candidate List since 16 December 2013, and cadmium at max 0.01 % by weight in the plastics listed in Annex XVII entry 23.
• Nickel-bearing pigments: PY53 under the nickel group of Annex XVII entry 27, for prolonged skin contact.
• Packaging metals: PPWR Article 5(4) (Reg. (EU) 2025/40) caps lead, cadmium, mercury and hexavalent chromium together at 100 mg/kg from 12 August 2026.

About 2,000 t of cadmium a year still go into pigments worldwide. Entries 23, 27 and 63 are explained on REACH Annex XVII restrictions. The lead-free replacements cover the shade space differently: bismuth vanadate PY184, PY53 and PBr24 on the inorganic side, and the benzimidazolone and isoindolinone yellows with the diketopyrrolopyrrole reds and oranges on the organic side.

Titanium dioxide: what the 2025 Court of Justice ruling changed#

Titanium dioxide has no harmonised EU hazard classification in force: the Carc. 2 entry introduced by Delegated Regulation (EU) 2020/217 was annulled by the General Court on 23 November 2022, and the Court of Justice dismissed the appeals on 1 August 2025. ECHA removed the entry from its website on 25 August 2025, and formal deletion from CLP Annex VI is pending, so titanium dioxide is never described as classified as a carcinogen in the EU.

Two other entries exist and neither concerns pigment bound in a plastic matrix. IARC classes inhaled titanium dioxide dust in Group 2B, and California Proposition 65 lists titanium dioxide as airborne, unbound particles of respirable size for cancer from 2 September 2011; both refer to dust exposure during handling, and the NIOSH recommendations of 2.4 mg/m3 for fine and 0.3 mg/m3 for ultrafine grades are workplace air standards for the powder. In food contact the pigment is authorised on both sides of the Atlantic.

Who Makes Colorants for Plastics? Suppliers and Market#

The colorant supply chain splits into four groups that rarely overlap: the titanium dioxide and carbon black producers, the organic pigment houses, the specialty makers of complex inorganic, effect and fluorescent pigments, and the masterbatch companies that sell the finished color. A compounder buys from at least two of them for one shade card. Company profiles are in the directory of pigment manufacturers and suppliers.

Volume sits with the white and black commodities. The USGS Mineral Commodity Summaries put world titanium dioxide pigment capacity at 9.9 Mt/yr for 2025, with China at 6.0 Mt/yr and the United States at 1.36 Mt/yr, US production at 1.0 Mt, a US landed duty-paid import price of USD 3,200/t, and the leading US uses ranked as paints, plastics and paper. Carbon black is larger in tonnage, at 13.2 Mt of global consumption in 2015, but only about 10 % goes to pigment use, since 70 % goes to tyres and 20 % to other rubber goods. The colorant family as a whole is 2 % of global plastic additive consumption by weight.

The last link is the concentrate, and the industry's consolidation has run through it: Avient, formed as PolyOne on 31 August 2000, bought the Clariant masterbatch business in 2020, DIC closed the acquisition of BASF Colors & Effects in 2021, and Sudarshan completed the Heubach acquisition on 3 March 2025. The color houses are listed under masterbatch manufacturers.

The table maps the eight supply segments to their producers and brand lines.

Segment-level volume and producer data for the concentrate business are on masterbatch market.

Complete List of Colorants for Plastics: 68 Substances#

The 68 colorant substances covered on this site are listed below with their Colour Index name, CAS number, chemical class, the polymers they are used in and their food-contact status in the EU and the United States. Rows follow the 9-type order used throughout this page, and every value repeats a fact stated above.

Types 6, 7 and 8, the effect, fluorescent and photoluminescent pigments, have no substance page yet, so no rows appear for them. Polymer cells reading "see substance page" mean that no polymer data for that substance is established in our source library.

All 68 colorants sit inside the plastic additives database, alongside the other additive families with their CAS numbers, functions, dosage ranges and regulatory status.

How Do Plastic Colorants Differ from Paint, Ink and Textile Colorants?#

The pigment can be the same substance in a can of paint and in a bag of masterbatch, but in a plastic there is no binder film: the colorant has to survive the melt, disperse in the polymer and stay where it was put for the life of the part. A paint or an ink holds its pigment in a separate binder that dries or cures around it, whereas a plastic disperses or dissolves the colorant in the polymer itself. That difference is why a plastics grade of a C.I. pigment is selected on three properties a coatings buyer never weighs: stability at the melt temperature, dispersibility under screw shear rather than in a mill base, and migration inside a solid polymer over years. The logic runs in reverse at recycling, because printing-ink diarylides that were stable on a printed film decompose at recycling temperatures.

Colorants that overlap other additive families#

Several colorants earn their place in a formulation twice, because the particle that gives the color also does something else to the polymer. Carbon black is the clearest case, since it screens ultraviolet radiation while colouring the part black, and titanium dioxide screens by scattering while it whitens. The overlaps are mapped below.

Coloring plastic after molding: paint, dye baths and why they are out of scope#

This page covers colorants that are compounded into the polymer before or during processing, which is how industrial parts, film, pipe and packaging are colored. Surface coloring is a different process with a different supply chain: spray paint, pad printing, in-mould decoration and hobby dye baths act on a finished part rather than on a melt. A colourant applied to a moulded surface is governed by adhesion and abrasion, while a colorant compounded into the polymer is governed by melt stability, dispersion and migration. Questions about painting or dyeing an existing plastic object fall outside the scope of this reference.

Do colorants affect plastic recycling? NIR sorting and pigment decomposition#

Colorants affect recycling twice: a black part pigmented with carbon black absorbs the near-infrared light that sorting lines use, so it is never identified, and printing-ink pigments carried into a recyclate can decompose at recycling temperatures. The APR Design Guide fixes the threshold in clause SORT-S-01, where a black or dark color with an L* below 40 or a near-infrared reflectance of 10 % or less fails. Carbon-black-free blacks are covered on NIR-sortable black colorants.

Two technical answers exist: Ampacet's REC-NIR-BLACK is a near-infrared-detectable black masterbatch, COTREP-certified for rigid polypropylene and HDPE packaging, and Shepherd Color's infrared black reflects near-infrared light so black plastic can be sorted.

The second effect is chemical rather than optical. Diarylide decomposition products are implicated in the yellowing of recycled polyethylene, and in a 2025 study in Materials all three tested printing-ink pigments were positive in miniaturised Ames tests after 30 minutes at 240 °C, with 2 of 4 samples positive in full OECD 471 plate tests. Color choices that keep a package sortable are set out on design for recycling.

Frequently asked questions about colorants for plastics#

The 4 questions below are the ones specifiers and buyers ask most often about colorants for plastics: how many pigment types exist, whether plastic can be permanently dyed, which classes reach 300 °C and whether titanium dioxide is banned.

What are the four types of pigments?#

No standard defines exactly four types of pigment: short summaries usually split them into inorganic, organic, effect and fluorescent pigments, while this reference sorts the whole colorant family into 9 types that also cover solvent dyes and optical brighteners. The four-way split breaks down as soon as loading, heat stability or food-contact status has to be specified, because inorganic pigments alone divide into the simple oxides and the calcined mixed metal oxides, which behave very differently above 250 °C.

Can you permanently dye plastic?#

Yes, but only in the melt and only in the right polymer: a solvent dye dissolves molecularly in an amorphous thermoplastic such as polystyrene, ABS, PMMA, polycarbonate or PET and stays there, while the same dye in polyethylene or polypropylene migrates to the surface. Polyolefins are therefore pigmented rather than dyed, since an insoluble pigment particle has nowhere to diffuse to and stays where the melt put it.

Which pigments are heat stable to 300 °C?#

The classes that reach polyamide and polycarbonate melt temperatures are the complex inorganic color pigments and the high-performance polycyclics, while the diarylide yellows are the first to fail, above about 200 °C. A complex inorganic color pigment holds because its coloring metal sits inside a calcined rutile, spinel or hematite lattice, and a diketopyrrolopyrrole holds thermally although it is not stable to acid or base. Per-grade heat stability in °C has to be taken from the supplier's data sheet.

Is titanium dioxide banned in plastics?#

No: titanium dioxide is authorised for food-contact plastics in the EU as FCM 610 with no specific migration limit and is listed in 21 CFR 178.3297 without a numeric limit, and it has no harmonised EU hazard classification in force since the Court of Justice dismissed the appeals on 1 August 2025. The IARC Group 2B entry and the California Proposition 65 listing of 2 September 2011 both refer to airborne, unbound particles of respirable size, a powder-handling exposure rather than pigment bound in a moulded part. The substances that do carry bans are listed on toxic plastic additives.