Triphenyl Phosphate: Properties, Uses in Plastics and Regulatory Status

Triphenyl phosphate (TPP, also written TPHP; CAS 115-86-6) is an aryl phosphate ester used as a halogen-free flame retardant and plasticizer in polycarbonate blends, PVC and cellulose acetate film. Because TPP carries its phosphorus in an aromatic ester rather than in a halogen, it sits in the halogen-free group that display makers turned to, which raises the question of what its 2024 listing as a Substance of Very High Concern now means for those compounds.

The European Chemicals Agency added triphenyl phosphate to the REACH Candidate List on 7 November 2024 for endocrine disrupting properties for the environment under Article 57(f), and its draft 13th Annex XIV recommendation of 2 February 2026 proposes the same substance for authorisation, with the consultation closed on 2 May 2026 and no final recommendation as of 23 September 2026. TPP is one of 87 flame-retardant pages in our directory of plastic additives, each with the same identity, dosage and regulatory fields.

This page holds the data-sheet view and the compliance view together: the identity that separates TPP from triphenyl phosphite, the mechanism, the physical constants, the four polymer systems that use the substance, 5 plastics applications, the comparison with RDP and BDP, a dated regulatory matrix and what a buyer has to specify.

Table T1. Triphenyl phosphate identity card.

Footnote: identity and physical data from PubChem CID 8289 and ECHA CHEM 100.003.739; regulatory entries from the EU and US legal texts cited in each section. Status as of 23 September 2026.

What Is Triphenyl Phosphate (TPP)?#

Triphenyl phosphate is the triphenyl ester of phosphoric acid, an aryl phosphate that carries about 9.5 wt% phosphorus and acts as both a flame retardant and a plasticizer in the polymers it is compounded into. Three phenol units esterify the three acidic hydroxyl groups of phosphoric acid, which leaves the formula C18H15O4P, a molecular weight of 326.3 g/mol and one P=O bond at the centre of the molecule. The phosphorus content of about 9.5 wt% follows arithmetically from that formula, since 30.974 g/mol of phosphorus sit in 326.3 g/mol of substance, and is a calculated value, not a supplier specification. Which names does the substance appear under on a data sheet?

Four designations cover one registry entry. Suppliers and compounders write triphenyl phosphate or the abbreviation TPP, chemical registries write phosphoric acid triphenyl ester and the inverted form phosphoric acid, triphenyl ester, and the environmental literature writes TPHP. The class label on technical documentation is aryl phosphate ester, and within flame-retardant classification the substance belongs to the organophosphate flame retardants, abbreviated OPFR. Two identifiers tie those names to one substance: CAS 115-86-6 and EC 204-112-2.

What does TPP stand for, and when is TPHP used instead?#

TPP stands for triphenyl phosphate, and the environmental and toxicological literature writes the same substance as TPHP or TPhP to keep it apart from triphenylphosphine and from other uses of the letters TPP. Materials data sheets, supplier catalogues and compounding papers use TPP, so this reference stays with TPP and treats TPHP and TPhP as synonyms. All three abbreviations resolve to CAS 115-86-6.

Is triphenyl phosphate the same as triphenyl phosphite?#

No: triphenyl phosphate (CAS 115-86-6) is a pentavalent phosphate ester used as a flame retardant, while triphenyl phosphite (CAS 101-02-0) is a trivalent phosphite used as a PVC co-stabilizer and secondary antioxidant. One oxygen atom separates the two formulas, C18H15O4P against C18H15O3P, and 16 g/mol separates the two molecular weights, 326.3 g/mol against 310.3 g/mol.

The functional distance is larger than the structural one. A phosphite decomposes hydroperoxides during processing and protects the polymer against thermal oxidation, while a phosphate ester interferes with combustion, so ordering the wrong substance produces a compound with no flame-retardant contribution. Triphenyl phosphite is a PVC co-stabilizer and secondary antioxidant, not a flame retardant, and carries its own data sheet on this site.

Is TPP a halogenated flame retardant?#

No: triphenyl phosphate contains no bromine and no chlorine, so it counts as a halogen-free flame retardant and falls outside the Ecodesign Regulation (EU) 2019/2021 ban on halogenated flame retardants in the enclosures and stands of electronic displays, in force since 1 March 2021. The formula C18H15O4P holds carbon, hydrogen, oxygen and phosphorus only, and that single structural fact is what moved aryl phosphates into television and monitor housings when the display rule took effect.

TPP belongs to the organophosphate flame retardants, the phosphate-ester group that replaced brominated grades in display housings. A halogen-free label describes the absence of bromine and chlorine, not the absence of regulatory duties: the Candidate List entry of 7 November 2024 applies whatever the halogen status of the compound.

How Does Triphenyl Phosphate Work as a Flame Retardant?#

Triphenyl phosphate works mainly in the gas phase, where phosphorus species interrupt the flame reactions, and partly in the condensed phase, where it forms phosphoric and pyrophosphoric acid that push the polymer towards char. Both routes start from the same event: the ester decomposes under fire conditions and releases its phosphorus, part of which reaches the flame and part of which stays in the melt.

Bernhard Schartel of BAM, the German Federal Institute for Materials Research and Testing, set out both routes for phosphorus flame retardants in his 2010 review in the journal Materials. Condensed-phase action covers charring, intumescence and the formation of an inorganic glass, while gas-phase action covers flame inhibition by phosphorus radicals. Schartel also states the price of the gas-phase route: flame inhibition lowers combustion efficiency without changing the effective heat of combustion, so a higher carbon monoxide yield always comes with it. Gas-phase and condensed-phase action are the two routes every class of flame retardants for plastics uses, in different proportions.

Those proportions shift with the polymer rather than with the additive. In the same 2010 work, bisphenol A bis(diphenyl phosphate) acts mainly in the gas phase in polycarbonate, while in PC/ABS it also enhances the charring of the polycarbonate phase. Does a gas-phase flame retardant then need an anti-drip additive? It does in most vertical-burning applications, the subject of the interactions section below, and the polymer dependence itself is explained on how flame retardants work.

Why is TPP also a plasticizer?#

TPP is a flame-retardant plasticizer: the same low-melting aromatic ester that releases phosphorus in a fire also separates polymer chains, which is why cellulose acetate film and some PVC compounds use it for both jobs at once. A solid that melts at 48 to 50 °C (118.4 to 122 °F) disperses into the matrix as a liquid at processing temperature and stays there as a small, mobile ester.

No plasticizer efficiency, substitution factor or Shore A value for triphenyl phosphate sits in our source library, so this page describes the dual function and states no number. As a flame-retardant plasticizer, TPP belongs to two additive families at once, and the classes are compared on plasticizers for plastics.

What Are the Physical and Chemical Properties of Triphenyl Phosphate?#

Triphenyl phosphate is a colourless solid that melts at 48 to 50 °C (118.4 to 122 °F), boils at 244 °C (471.2 °F) under 10 mmHg and has a density of 1.184 g/mL. Seven recorded values define its physical behaviour, and all except the calculated phosphorus content come from PubChem CID 8289.

Table T2. Physical and chemical properties of triphenyl phosphate.

Footnote: water solubility, vapour pressure and the octanol-water partition coefficient are not recorded in our source library, so no row is filled for them. The boiling point is valid only at 10 mmHg and is not an atmospheric boiling point.

The melting range decides how the additive enters a compound. TPP is fed as a solid through the same gravimetric equipment that handles powders and flakes, and it melts early in the extruder barrel rather than at the melting point of the polymer, which is a different handling case from the liquid oligomeric aryl phosphates RDP and BDP, metered by pump. The boiling point belongs to a reduced-pressure measurement and describes distillation behaviour, not loss during processing.

Which Polymers Use Triphenyl Phosphate, and at What Dosage?#

Triphenyl phosphate is used in four polymer systems: polycarbonate blends (PC/ABS), PPE/HIPS blends, PVC and cellulose acetate film, plus casting resins. In the two engineering blends the substance works as a flame retardant, in PVC and cellulose acetate film it works as a flame-retardant plasticizer, and in casting resins it works as a flame retardant in a thermoset matrix.

No TPP loading in phr or wt% is recorded in our source library for any of those polymers, and this page states none. The class benchmark that does exist carries a different substance name: a 2024 PC/ABS study reached UL 94 V-0 with 20 wt% of the aryl oligophosphate BAPDP together with 0.4 wt% PTFE, which shows the order of magnitude at which aryl phosphates are dosed in that blend and does not transfer to TPP. Loadings for triphenyl phosphate are formulation-specific and have to be taken from the supplier's technical data sheet.

Table T3. Polymers that use triphenyl phosphate.

Footnote: loadings for triphenyl phosphate are not recorded in our source library; request the supplier's technical data sheet.

TPP in polycarbonate blends (PC/ABS) and PPE/HIPS#

PC/ABS is the main plastics market for triphenyl phosphate, because the aryl phosphate class both inhibits the flame in the gas phase and pushes the polycarbonate phase to form char. Polycarbonate is the char former and ABS the fuel-rich phase, so the flame retardant serves two phases at once. The full selection logic for PC and PC/ABS sits on flame retardants for polycarbonate.

PPE/HIPS blends follow the same pattern with a different char former. Polyphenylene ether chars strongly on its own, and the aryl phosphate contributes flame inhibition and plasticizes the stiff PPE phase. The 2024 PC/ABS result quoted above, 20 wt% BAPDP with 0.4 wt% PTFE for UL 94 V-0, is the class reference for the dosage range, not a TPP loading.

Three additives decide the rest of these blends: the anti-drip agent, the impact modifier and the light stabilizer. That package, from impact modifier to UV absorber, is set out on additives for polycarbonate and PC/ABS.

TPP in PVC#

In PVC, triphenyl phosphate works as a flame-retardant plasticizer, replacing part of the conventional plasticizer load with an ester that carries its own phosphorus. PVC is inherently flame-retarded to a degree by its own chlorine content, so the phosphate ester is chosen where the plasticizer must not undo that behaviour, which a purely hydrocarbon-based ester does.

No phr value, no limiting oxygen index and no smoke figure for TPP in PVC is recorded in our source library, so this page publishes none. Smoke is the second half of the PVC fire question, and smoke suppressants and the aluminium hydroxide route are covered on flame retardants and smoke suppressants for PVC.

TPP in cellulose acetate film and casting resins#

Cellulose acetate film is the oldest plastics use of triphenyl phosphate, where the same ester plasticizes the film and raises its resistance to ignition. Casting resins use the substance for the flame-retardant function alone, in a thermoset matrix that is cured rather than compounded, which removes the melt-feeding question entirely.

What Are the Uses of Triphenyl Phosphate? 5 Applications in Plastics#

Triphenyl phosphate is used in 5 plastics applications: electrical and electronic housings, PVC compounds, cellulose acetate film, casting resins and flame-retardant plasticizer blends. The 5 plastics applications are listed below, each with the polymer that carries it.

• Electrical and electronic housings in PC/ABS and PPE/HIPS blends, where a halogen-free rating is the requirement.
• PVC compounds, where the substance plasticizes and contributes phosphorus at the same time.
• Cellulose acetate film and sheet, where one additive covers plasticizing and ignition resistance.
• Casting resins, where the flame retardant is dissolved in the resin before cure.
• Flame-retardant plasticizer blends, where TPP carries the phosphorus content of a mixed plasticizer load.

Hydraulic fluids and adhesives are recorded as non-plastic uses and sit below the contextual border of this reference, which covers additives used in plastics.

Electrical and electronic housings in PC/ABS and PPE/HIPS#

Electrical and electronic housings are the application that drives aryl phosphate demand, because Regulation (EU) 2019/2021 has banned halogenated flame retardants in the enclosures and stands of electronic displays since 1 March 2021. A television bezel, a monitor stand and a laptop base are therefore formulated around phosphorus chemistry in the European market. ABS on its own needs a different system, set out on flame retardants for ABS.

The parts themselves are thin. A housing wall of 1.5 mm or less has to pass its rating at that thickness, which is why a class benchmark such as 20 wt% aryl oligophosphate with 0.4 wt% PTFE is quoted with its polymer and its test geometry rather than as a general dosage.

Electrical requirements run alongside the fire requirements in the same part. Glow-wire performance under IEC 60695-2-12 and -2-13 and comparative tracking index under IEC 60112 are specified for enclosures holding live parts, and those requirements are listed under additives for electrical and electronics.

Film, sheet and casting resins#

Cellulose acetate film, sheet and casting resins use triphenyl phosphate where a single additive has to plasticize and retard flame at the same time. Cellulose acetate is a cellulose ester rather than a petrochemical thermoplastic and needs a plasticizer to be processable at all, so a plasticizer that also carries phosphorus removes one ingredient from the formulation. Casting resins take the substance for the fire performance alone. Neither use has a recorded loading in our source library.

How Does TPP Perform in a Flame-Retardant Compound?#

A gas-phase flame retardant such as triphenyl phosphate buys its rating at the cost of combustion efficiency, which means a higher carbon monoxide yield and, in styrenic blends, more smoke. Every member of the phosphorus flame retardants group trades combustion efficiency for the rating, as Schartel's 2010 analysis at BAM sets out, so the performance question is the rating together with the smoke and the toxic-gas yield.

The ENFIRO project, funded by the European Union under the Seventh Framework Programme as grant 226563 and concluded in 2012, compared halogen-free systems and found that RDP and BDP in styrenics gave more smoke than the alternatives assessed. That result belongs to the aryl phosphate class in styrenic matrices, not to triphenyl phosphate as a measured property.

No UL 94 rating, limiting oxygen index, cone calorimeter value, heat deflection temperature or volatility figure for TPP is recorded in our source library, and none is stated here. What can be given are the polymer baselines: unmodified polycarbonate rates UL 94 HB to V-2 and has a limiting oxygen index of 25 to 29 vol % O2, the starting point any PC/ABS formulation improves on. Compound values have to come from the supplier's data sheet or from the converter's own testing. To shortlist a system for a given polymer and rating, use the flame retardant selector by polymer and UL 94 rating.

Table T4. Performance indicators and the standards that measure them.

Which flammability and oxygen-index tests apply to TPP compounds?#

Two tests decide whether a TPP compound passes: UL 94, which rates afterflame time and dripping on a vertical bar, and the limiting oxygen index, which reports the minimum oxygen concentration that still supports flaming combustion. The V-0, V-1 and V-2 criteria and the specimen geometry are set out on UL 94 flammability ratings.

V-0 requires each afterflame to last no more than 10 s, the total for 5 specimens to stay at or below 50 s, afterflame plus afterglow after the second flame application to stay at or below 30 s, no burning up to the clamp and no ignition of the cotton below the specimen. V-1 allows 30 s, 250 s and 60 s with no cotton ignition, and V-2 applies the V-1 times but permits flaming drips that ignite the cotton. The specimen measures 125 x 13 mm and receives two 10 s applications of a 20 mm (50 W) flame, and every rating is quoted with its thickness.

The oxygen index measures a different quantity: the minimum oxygen concentration in vol % in a flowing oxygen and nitrogen mixture that just supports flaming combustion, against an air baseline of about 21 vol % O2, under ASTM D2863-23e1 or ISO 4589-2. Baseline values per polymer are tabulated on limiting oxygen index (LOI).

How Does TPP Interact with Other Additives?#

Triphenyl phosphate is rarely the only flame-retardant ingredient in a compound: it is combined with an anti-drip additive, blended with heavier aryl oligophosphates and matched to a polymer that can form char. The 3 interactions that decide a TPP formulation are listed below.

1. Anti-drip PTFE, dosed at about 0.4 to 0.5 wt% in PC/ABS alongside an aryl phosphate, with a patent range of 0.05 to 10 phr active PTFE and usually supplied as SAN-encapsulated PTFE (TSAN) in ratios from 40/60 to 60/40.
2. Aryl oligophosphate blend partners, RDP and BDP, which carry the same phosphorus chemistry at higher molecular weight and lower volatility.
3. The char-forming polymer phase, polycarbonate above all, which converts condensed-phase phosphoric acid into a protective layer.

A gas-phase flame retardant does not prevent dripping, and a vertical-burn rating depends on whether the drips ignite the cotton below the specimen, which is why the 2024 PC/ABS result pairs 20 wt% of an aryl oligophosphate with 0.4 wt% PTFE. The third interaction runs the other way: in one comparative study, RDP alone did not achieve a rating in ABS or EVA at 20 to 30 wt%, so an aryl phosphate without a char-forming phase has little to work with. PTFE as a plastic additive is the anti-drip partner at about 0.4 to 0.5 wt% in PC/ABS.

What Is the Regulatory Status of Triphenyl Phosphate?#

Triphenyl phosphate has been on the REACH Candidate List since 7 November 2024 for endocrine disrupting properties for the environment, is proposed but not yet listed for authorisation, is designated a high-priority substance under TSCA in the United States and is not on the California Proposition 65 list (status 23 September 2026). Two cells are open: the REACH registration status and the EU food-contact status are being verified.

Table T5. Regulatory matrix for triphenyl phosphate, as of 23 September 2026.

Instruments, not substance classes, decide what a compound may contain, and the rows above answer three questions: what has to be communicated, what the article may contain and what the label has to say. How bans, furniture standards and UL requirements interact is set out on flame retardant regulations.

Is triphenyl phosphate an SVHC?#

Yes: the European Chemicals Agency added triphenyl phosphate to the REACH Candidate List on 7 November 2024 because of its endocrine disrupting properties for the environment under Article 57(f). That update added one substance, and triphenyl phosphate was it, which makes the entry easy to date and easy to verify. A Candidate List entry is not a ban and not an authorisation requirement: it is an information obligation that starts on the day of inclusion. Every additive on the SVHC Candidate List is recorded there with its inclusion date and its Article 57 reason, including the aryl phosphates that are absent from it.

What does the REACH SVHC listing require from compounders and article producers?#

Candidate List inclusion triggers 4 duties whenever triphenyl phosphate is present above 0.1 % by weight in an article, and the threshold applies to each component article of a complex product, not to the whole product. The Court of Justice of the European Union settled that reading in case C-106/14 on 10 September 2015. The 4 duties are listed below.

1. Communicate to recipients under Article 33, immediately on inclusion, and answer consumer requests within 45 days.
2. Notify ECHA under Article 7(2) above 0.1 % w/w in the article and 1 tonne per year per actor, within 6 months of inclusion.
3. Notify the SCIP database under Article 9(1)(i) of the Waste Framework Directive, in force since 5 January 2021.
4. Supply a safety data sheet on request for a non-classified mixture containing 0.1 % or more, under Article 31(3).

The registration, communication and notification duties under REACH and plastic additives apply to importers of finished parts as well as to compounders.

Could TPP be added to the REACH Authorisation List?#

Triphenyl phosphate is proposed for the REACH Authorisation List but is not on it: ECHA published a draft 13th recommendation on 2 February 2026 naming TPP alongside UV-326, UV-329 and photoinitiator 379, and the consultation closed on 2 May 2026 without a final recommendation so far. A draft recommendation is the first formal step of a process that runs through a final ECHA recommendation, a Commission decision and an amending regulation before any entry exists.

No latest application date and no sunset date exist for triphenyl phosphate, because those dates are created by the amending regulation that has not been adopted. Latest application dates and sunset dates for the additives already listed are on REACH Annex XIV Authorisation List.

Is triphenyl phosphate regulated in the United States under TSCA?#

Triphenyl phosphate is a TSCA high-priority substance: the US Environmental Protection Agency designated it for risk evaluation in December 2019 and published the final scope of that evaluation in August 2020. The 2016 Chemical Data Reporting cycle records a national volume band of 1 to 10 million lb/yr for the substance, with flame-retardant and plasticizer use in plastics and in foam seating.

The outcome of the risk evaluation and the status of the proposed significant new use rule are not established in our source library and are not stated here; both are open verification items to be confirmed against the EPA record before any determination is quoted. How prioritisation, risk evaluation and significant new use rules work, and what each step does and does not restrict, is explained on TSCA and plastic additives.

Why does the CPSIA rule 16 CFR 1308 name TPP for ABS?#

The US Consumer Product Safety Commission names triphenyl phosphate in 16 CFR 1308.2 as one of the additives an ABS part may contain and still be treated as free of the specified phthalates, which removes the third-party phthalate testing requirement for that part. The rule lists plastics determined not to contain those phthalates, among them polypropylene, polyethylene, the polystyrene family of GPPS, MIPS, HIPS and SHIPS, and ABS, each only with the additives the rule names, which for ABS are triphenyl phosphate and hydrocarbon oil.

The companion rule sets the limits. 16 CFR 1307 restricts DEHP, DBP, BBP, DINP, DIBP, DPENP, DHEXP and DCHP to 0.1 % in children's toys and childcare articles, and the exemption in 1308 exists because the listed plastics are not made with those plasticizers. The full list of exempt plastics and their permitted additives is on CPSIA phthalate limits.

Is triphenyl phosphate listed under California Proposition 65?#

No: triphenyl phosphate is not on the California Proposition 65 list as published on 31 July 2026, unlike the chlorinated organophosphate TCEP, listed for cancer on 1 April 1992. A warning obligation for the substance therefore does not arise from Proposition 65, although it can arise from other listed ingredients in the same compound. Listing dates for every flame retardant are on California Proposition 65.

Which US states restrict organophosphorus flame retardants?#

California restricts triphenyl phosphate as an organophosphorus flame retardant: AB 2998 has banned halogenated and organophosphorus flame retardants above 1,000 ppm in juvenile products, mattresses and upholstered furniture since 1 January 2020. New York bans organohalogen flame retardants in electronic display enclosures and stands from 1 January 2024, a rule that leaves TPP untouched because the substance carries no halogen. California, New York and Washington rules are compared on US state laws on plastic additives.

Is TPP allowed in food-contact plastics?#

In the United States, triphenyl phosphate is cleared only as a component of adhesives under 21 CFR 175.105, which is an indirect food additive clearance and not a clearance for the plastic itself. An adhesive clearance covers the substance in a laminating or sealing layer under the conditions that section sets, and it says nothing about a moulded part or a film in direct contact with food.

The EU food-contact status of triphenyl phosphate under Regulation (EU) No 10/2011 is being verified and is not stated on this page in either direction. The difference between an adhesives clearance and a polymer clearance is explained on FDA food contact rules for plastic additives, and the same distinction decides which document a converter has to request from a supplier.

Is Triphenyl Phosphate Safe? Health, Safety and Environmental Profile#

The hazard on record for triphenyl phosphate is environmental: companies notifying the substance to ECHA report the aquatic hazard statements H400 and H410, and its 2024 SVHC listing rests on endocrine disrupting properties for the environment under Article 57(f), not on a human-health endpoint. No harmonised entry under the CLP Regulation (EC) No 1272/2008 is recorded in our source library, so that classification is a notifier self-classification.

Four categories of data that readers expect on a substance page are absent from our source library for TPP: no LD50, no NOAEL, no human biomonitoring value and no house-dust concentration. This page states none of them rather than paraphrasing figures from toxicology abstracts or exposure databases. What the human studies do and do not show is summarised on flame retardants and human health, the page that carries that evidence with its sources.

The Article 57(f) route itself is worth reading precisely. It covers substances of equivalent level of concern, and for triphenyl phosphate the identified concern is endocrine disruption in the environment, an ecotoxicological conclusion reached for the aquatic compartment rather than a statement about consumer exposure. Article 57(f) listings for endocrine disruption are explained on endocrine disruptors in plastics, alongside the other additives listed on the same ground.

What Are the Alternatives to Triphenyl Phosphate?#

The 3 main alternatives to triphenyl phosphate in the same compounds are the aryl oligophosphates RDP and BDP, which are liquids and neither of which is on the Candidate List, and the halogen-free mineral and phosphinate systems used where no aryl phosphate is acceptable. Molecular weight is the variable that separates the first two from TPP, and polymer compatibility is the variable that separates the third group from all three aryl phosphates.

Table T6. Triphenyl phosphate compared with RDP, BDP and aluminium diethylphosphinate.

Footnote: SVHC status as of 23 September 2026. RDP and BDP are dual-CAS substances: the monomer CAS number and the oligomeric commercial-product CAS number are both in use.

TPP vs RDP#

RDP is the liquid replacement for triphenyl phosphate in PC/ABS: at 574.5 g/mol it is heavier and less volatile than TPP at 326.3 g/mol, it is not on the Candidate List, and it is dosed as a liquid instead of as a solid. Resorcinol bis(diphenyl phosphate) carries CAS 57583-54-7 and EC 260-830-6 for the monomer and CAS 125997-21-9 for the commercial oligomer, has the monomer formula C30H24O8P2, and is sold by ICL Industrial Products as Fyrolflex RDP.

Two consequences follow for a plant: liquid metering replaces solid feeding, and the higher molecular weight reduces volatility during compounding. The limit of the substitution shows in the matrix, since in one comparative study RDP alone did not achieve a rating in ABS or EVA at 20 to 30 wt%. RDP flame retardant is dosed as a liquid and is not on the Candidate List.

TPP vs BDP#

BDP is the heaviest of the three aryl phosphates at 692.6 g/mol, which is why PC/ABS housings for IT equipment, chargers and displays use it where TPP would be too volatile. Bisphenol A bis(diphenyl phosphate) carries CAS 5945-33-5 and EC 425-220-8 for the monomer and CAS 181028-79-5 for the oligomer, has the monomer formula C39H34O8P2, is supplied by ICL Industrial Products as Fyrolflex BDP and is not on the Candidate List; notifiers report H413.

Its structure contains a bisphenol A moiety, which is a statement about the molecule and not about a restriction: no restriction of BDP is recorded in our source library, and the EU bisphenol A measures concern food-contact materials rather than this use. BDP flame retardant is the ester Schartel's 2010 work used to show gas-phase action in polycarbonate and added char in PC/ABS.

TPP vs halogen-free mineral and phosphinate systems#

Where no aryl phosphate is acceptable, the halogen-free route runs through metal phosphinates and mineral fillers: aluminium diethylphosphinate carries 23.3 to 24.0 wt% phosphorus and reaches UL 94 V-0 at about 15 wt% in PA 6T/66, a loading no aryl phosphate matches. That figure comes from Clariant's Exolit OP 1230 at 1.6 and 0.8 mm, and the phosphinate decomposes above 300 °C, which is what makes it usable in engineering polyamides.

The substitution does not run in the other direction. Aluminium diethylphosphinate works in polyamides and PBT, not in PC/ABS, so it is an alternative at the part-design level rather than a drop-in replacement. The ENFIRO project reported good environmental and health profiles for ammonium polyphosphate, aluminium diethylphosphinate, aluminium hydroxide, magnesium hydroxide, melamine polyphosphate, DOPO, zinc stannate and zinc hydroxystannate, and those routes are compared on halogen-free flame retardants.

Who Manufactures Triphenyl Phosphate? Grades and Suppliers#

Triphenyl phosphate is supplied by the phosphate-ester flame-retardant producers rather than under a single dominant brand, and our source library records no trade name for TPP itself, so the grade has to be specified by purity, melting range and supplier documentation. No manufacturer is named for the substance here for the same reason: assigning a producer's brand line to TPP without a recorded mapping would be a guess.

What is recorded is the class-level supplier landscape. Lanxess markets the flame-retardant and plasticizer brand lines Disflamoll, Levagard, Reofos, Firemaster and Emerald Innovation, completed with the Chemtura acquisition on 21 April 2017, and ICL Industrial Products makes the aryl oligophosphates Fyrolflex RDP and Fyrolflex BDP. Producers and their brand lines are in the directory of flame retardant manufacturers and suppliers.

Table T7. What to specify in a triphenyl phosphate enquiry.

No price level for triphenyl phosphate sits in our source library, so this page publishes none. Buyers should ask for the supplier's technical data sheet, safety data sheet and a written SVHC statement covering the 0.1 % threshold, the document a downstream customer requests first after the Candidate List entry of 7 November 2024.

How Do Aryl Phosphates Fit into the Wider Flame Retardant Family?#

Triphenyl phosphate is the simplest member of the aryl phosphate class, the group of phosphate esters that sits beside brominated, chlorinated, mineral, intumescent and phosphinate flame retardants in a market worth USD 8.1 to 9.3 billion in 2025 on analyst estimates. More than 2 million tonnes of flame retardants were consumed in 2013, and the phosphorus-based share of that volume has grown with every halogen restriction since.

Inside the class, the members differ by molecular weight rather than by chemistry: TPP at 326.3 g/mol, RDP at 574.5 g/mol and BDP at 692.6 g/mol carry the same aryl phosphate function at three levels of volatility. Segment sizes and supply risks are tracked on the flame retardants market page.

PIP (3:1), the isopropylated relative restricted under TSCA#

PIP (3:1), the isopropylated version of triphenyl phosphate, is the one aryl phosphate with a hard US deadline: under 40 CFR 751.407 the distribution of most articles containing it is prohibited after 31 October 2026. The substance, phenol isopropylated phosphate (3:1), CAS 68937-41-7 and EC 273-066-3, is a UVCB aryl phosphate ester used as a flame-retardant plasticizer in PVC, polyurethane and E&E articles.

The TSCA 6(h) PBT rule of 2021, revised on 19 November 2024 and effective 21 January 2025, prohibited processing and distribution for use in articles after 31 October 2024, allows new motor-vehicle parts until 21 November 2039 and replacement parts until 19 November 2054, and excludes circuit boards and wire harnesses. PIP (3:1) (isopropylated triphenyl phosphate) carries deadlines that TPP does not.

What are organophosphate flame retardants (TPP, RDP, BDP, TCPP)?#

Organophosphate flame retardants are phosphate esters that release phosphorus species into the flame, and the four used most in plastics are triphenyl phosphate, RDP, BDP and TCPP. The 4 are listed below with their CAS numbers and main polymers.

• Triphenyl phosphate (CAS 115-86-6), the solid aryl phosphate for PC/ABS, PPE/HIPS, PVC and cellulose acetate film.
• RDP (CAS 57583-54-7 monomer, 125997-21-9 oligomer), the liquid aryl oligophosphate for PC/ABS and PPE/HIPS.
• BDP (CAS 5945-33-5 monomer, 181028-79-5 oligomer), the heaviest aryl oligophosphate, for PC/ABS and PPE blends.
• TCPP (CAS 13674-84-5), the chlorinated member, used mainly in polyurethane foam.

Regulatory treatment splits the group. TCPP and TDCPP (CAS 13674-87-8) are not SVHCs and carry no REACH Annex XVII restriction, the EU toy rules limit TCEP, TCPP and TDCP to 5 mg/kg under Directive 2014/79/EU, and triphenyl phosphate is the only one of the four on the Candidate List. An ECHA investigation covering organophosphorus flame retardants is reported to be running, with a first report given as December 2026; that date and the inclusion of TPP are not established. The class page for phosphate ester flame retardants compares the four.

Non-plastics uses of triphenyl phosphate#

Outside plastics, triphenyl phosphate is used in hydraulic fluids and adhesives, which are outside the scope of this reference. PlasticAdditives.net covers additives used in plastics, so those two uses are named for completeness and not developed further.

Is triphenyl phosphate banned anywhere?#

No: triphenyl phosphate is not banned in the EU or the United States, but its SVHC listing of 7 November 2024 triggers communication duties above 0.1 % by weight, its proposed Annex XIV entry of 2 February 2026 is not in force, and California's AB 2998 has banned organophosphorus flame retardants above 1,000 ppm in juvenile products, mattresses and upholstered furniture since 1 January 2020.

Does TPP migrate out of plastics?#

Triphenyl phosphate is the most mobile of the three aryl phosphates because it is the lightest: at 326.3 g/mol it is roughly half the molecular weight of BDP at 692.6 g/mol, which is why formulators move to the oligomers when volatility or migration matters. No measured migration, extraction or volatility value for TPP is recorded in our source library, so this page gives no loss figure. Why molecular weight governs loss is explained on additive migration in plastics.

What is TPHP in nail polish?#

TPHP in nail polish is the same substance as the TPP in a plastics compound, CAS 115-86-6, used there as a film former and plasticizer rather than as a flame retardant. Cosmetics sit outside this reference, which covers additives used in plastics, so no cosmetic exposure data is quoted on this page.