Dicumyl Peroxide: Properties, Uses in Plastics and Regulatory Status

Dicumyl peroxide (DCP, CAS 80-43-3) is a monofunctional dialkyl peroxide used as a radical crosslinking agent for polyethylene, EVA and POE, and it is the workhorse peroxide of medium- and high-voltage XLPE cable insulation. It is an organic peroxide, not hydrogen peroxide and not the dibenzoyl or dilauroyl peroxides that share the word: those initiate vinyl polymerisation, while DCP builds carbon-carbon bridges between finished polymer chains at 170 °C (338 °F). Everything about its use follows from one number: how fast it decomposes at a given temperature.

Its regulatory position changed in 2024. Dicumyl peroxide is registered under REACH, has been on the REACH Candidate List since 27 June 2024 as toxic for reproduction under Article 57(c), carries a harmonised CLP classification as an organic peroxide of type F (H242) and a Category 1B reproductive toxicant (H360D), and is not on Annex XIV. DCP is one of 20 crosslinking-agent pages in our directory of plastic additives, each with the same identity, dosage and regulatory fields.

This page holds the data sheet and the compliance record together: identity, crosslinking mechanism and its 5 byproducts, half-life, dosage per polymer in phr, 5 application areas, gel and hot-set targets, a regulatory matrix dated 24 September 2026, the comparison with BIPB, DHBP, DTBP, silane and e-beam crosslinking, and the grades a buyer can source.

Table T1. Dicumyl peroxide identity card.

What Is Dicumyl Peroxide (DCP)?#

Dicumyl peroxide is a monofunctional dialkyl peroxide: one oxygen-oxygen bond sits between two cumyl groups, and heat splits it into two cumyloxy radicals that start the crosslinking reaction. Each cumyl group is a 1-methyl-1-phenylethyl fragment, which is why the systematic name is bis(alpha,alpha-dimethylbenzyl) peroxide and why the molecule weighs 270.4 g/mol for a formula of C18H22O2. Those two aromatic groups carry no reactive site of their own, so the whole chemistry of the substance lives in the single O-O bond.

What separates DCP from the hydrogen peroxide and benzoyl peroxide that dominate the search results? Hydrogen peroxide is an inorganic oxidiser, while dibenzoyl and dilauroyl peroxide are diacyl peroxides that decompose far lower and initiate vinyl polymerisation. Dicumyl peroxide is dosed into a finished thermoplastic during compounding, and as a radical initiator that builds a network rather than a chain it belongs to the crosslinking agents for polymers, the family that also covers silanes and coagents.

What does DCP stand for, and which names mean the same substance?#

DCP stands for dicumyl peroxide, the trade abbreviation for bis(alpha,alpha-dimethylbenzyl) peroxide, CAS 80-43-3 and EC 201-279-3. The abbreviation DCUP means the same substance, and so do the synonyms cumyl peroxide and bis(1-methyl-1-phenylethyl) peroxide, which appear in chemical databases and in older rubber literature. Some supplier pages print a different CAS number for dicumyl peroxide; the registered number is 80-43-3, and a specification that carries any other number is describing a different chemical.

What type of peroxide is dicumyl peroxide?#

Dicumyl peroxide belongs to the dialkyl peroxides, the most heat-stable of the crosslinking classes, and it is monofunctional: each molecule carries one oxygen-oxygen bond and therefore releases two radicals. The dialkyl class is one of 6 peroxide classes used to crosslink polymers, each sitting at a different point on the temperature scale.

• Dialkyl peroxides, such as DCP, di-tert-butyl peroxide (DTBP), DHBP, BIPB, tert-butyl cumyl peroxide and the hexyne peroxide.
• Peroxycarbonates, such as TBEC (Trigonox 117) and TAEC (Trigonox 131).
• Peroxyketals, such as Trigonox 29.
• Peroxyesters, such as Trigonox 17.
• Cyclic trioxepanes, such as Trigonox 311.
• Cyclic triperoxonanes, such as Trigonox 301.

The class hub for organic peroxides for polymers compares those classes on half-life, processing window and polymer fit.

What are the two types of peroxide a compounder deals with?#

In polymer compounding the practical split is monofunctional against bifunctional: dicumyl peroxide carries one peroxide bond, while BIPB and DHBP carry two and release up to four radicals per molecule. A bifunctional peroxide therefore delivers more radicals per kilogram dosed, which is the reason its recommended level in the same polymer is lower than the DCP level given further down this page.

What is the active oxygen content of dicumyl peroxide?#

Dicumyl peroxide has a theoretical active oxygen content of 5.92 %, the lowest of the common crosslinking peroxides, because its two cumyl groups are heavy relative to the single peroxide bond. The practical consequence is a weight penalty: reaching the same radical yield takes more DCP by weight than DHBP at 11.02 % active oxygen, DTBP at 10.94 % or BIPB at 9.45 %, and roughly the same weight as TBEC at 6.49 %. Active oxygen is the figure a purchaser compares across grades, because it measures the reactive fraction, not the delivered mass.

How Does Dicumyl Peroxide Crosslink Polyethylene?#

Dicumyl peroxide crosslinks polyethylene by thermal homolysis: the oxygen-oxygen bond breaks into two cumyloxy radicals, each abstracts a hydrogen atom from a polymer chain, and two of the resulting macroradicals combine into a permanent carbon-carbon crosslink. The cumyloxy radical has two routes open to it. It abstracts hydrogen and becomes cumyl alcohol, which can lose water to form alpha-methylstyrene, or it beta-cleaves into acetophenone and a methyl radical, and that methyl radical picks up hydrogen to form methane. Both routes leave a macroradical on the polyethylene backbone, and the pairing of two macroradicals creates the network.

Does crosslinking make a polymer stronger? It changes the class of the material rather than raising a strength number: crosslinked polyethylene stops melting and behaves as a thermoset, while the peroxide network costs tensile and tear strength against a sulfur-cured reference. One 2024 review in ACS Applied Polymer Materials estimates crosslinked polyolefins at about 5 to 10 % of the PE market, growing 6 to 8 % a year.

Which byproducts does DCP leave in the polymer?#

Dicumyl peroxide leaves 5 decomposition byproducts in the polymer: methane, acetophenone, cumyl alcohol, alpha-methylstyrene and water. The 5 byproducts and their origin are listed below.

• Methane, formed when the methyl radical from beta-cleavage abstracts hydrogen.
• Acetophenone, the second product of that beta-cleavage step.
• Cumyl alcohol, formed when the cumyloxy radical abstracts hydrogen instead.
• Alpha-methylstyrene, formed when cumyl alcohol loses water.
• Water, released in that same dehydration step.

None of these is inert in an electrical application. The polar and mobile residues raise the conductivity of high-voltage insulation, which is the main technical argument for lower-byproduct peroxides and for the peroxide-free insulation concepts surveyed in a 2024 Advanced Materials review.

Why must XLPE cable insulation be degassed?#

XLPE cable cores are degassed because the methane and acetophenone left by dicumyl peroxide raise the conductivity of the insulation and have to diffuse out before the cable is qualified. Degassing follows vulcanisation and works by holding the core warm enough for the small molecules to migrate out of the polymer without damaging it. In laboratory practice the same 2024 Advanced Materials review reports 70 °C (158 °F) for 24 hours; at industrial cable-drum scale the operation takes days, and no single duration applies across conductor sizes and insulation thicknesses.

Why does DCP degrade polypropylene instead of crosslinking it?#

Polypropylene carries a tertiary hydrogen on every second carbon, so the macroradical that dicumyl peroxide creates splits the chain by beta-scission instead of joining two chains. The tertiary macroradical is stabilised by the adjacent methyl group and cleaves rather than waiting for a partner, so molecular weight falls and the molecular-weight distribution narrows. The same radical that builds a network in polyethylene therefore starts polymer degradation in polypropylene.

Producers use the effect deliberately. Controlled-rheology polypropylene is made by peroxide modification of polypropylene, and the published reactive-extrusion data use DHBP rather than DCP: 0 to 600 ppm, with the melt index of mild and harsh screw designs diverging above 400 ppm and 200 ppm cited for staple fibre. Coagents suppress the scission where crosslinking rather than visbreaking is wanted.

What Are the Physical and Thermal Properties of Dicumyl Peroxide?#

Dicumyl peroxide is a white crystalline solid that melts at 39 to 40 °C (102.2 to 104 °F) and decomposes rather than boiling, with a density of 1.02 g/cm3. The crystalline grade Perkadox BC-FF carries an assay of at least 99 %, and every thermal figure below comes from the Nouryon product data sheet.

Table T2. Dicumyl peroxide physical and thermal properties.

The Nouryon product data sheet gives 39 to 40 °C (102.2 to 104 °F), while lab-catalogue and encyclopedia entries print 38 to 41 °C, so check which data source a specification refers to. No solubility, vapour-pressure or flash-point value for dicumyl peroxide sits in our source library, so this page prints none.

What is the half-life of dicumyl peroxide?#

Dicumyl peroxide has a 10-hour half-life temperature of 112 °C (233.6 °F), a 1-hour half-life at 132 °C (269.6 °F) and a 0.1-hour half-life at 154 °C (309.2 °F), all measured in dilute chlorobenzene solution. Decomposition follows first-order kinetics, so the half-life at any temperature comes from two published constants:

kd = A x exp(-Ea / RT), and t(1/2) = ln2 / kd, with Ea = 152.67 kJ/mol and A = 9.24 x 10^15 s^-1 for dicumyl peroxide.

Those constants are published per grade and describe decomposition in a dilute solvent, so a half-life measured in chlorobenzene is a comparison basis between peroxides, not a cure-time prediction for a filled compound, where fillers, antioxidants and shear change the effective rate. Values for other peroxides run through the same two equations in the organic peroxide half-life and dosage calculator.

What do SADT and Ts max mean for storing DCP?#

The self-accelerating decomposition temperature (SADT) of dicumyl peroxide is 75 °C (167 °F), and its maximum recommended storage temperature (Ts max) is 30 °C (86 °F). SADT is the lowest temperature at which self-accelerating decomposition may occur in the substance as packaged for transport, and it is determined by the UN Heat Accumulation Storage Test rather than calculated from the half-life data. Ts max sits 45 °C (81 °F) below the SADT and is the temperature the supplier recommends the packaging is kept under.

Which Polymers Use Dicumyl Peroxide, and at What Dosage?#

Dicumyl peroxide is dosed in polyethylene at 1.4 to 6.8 phr of the 40 % supported formulation, which corresponds to roughly 0.56 to 2.7 phr of active peroxide. Why do two data sheets give different DCP levels for the same compound? One counts the formulation as delivered, usually a 40 % masterbatch or supported powder such as Perkadox BC-40, and the other counts the active peroxide inside it, so a level quoted without its basis is unusable. Every recipe below states its basis, and the wider package that runs alongside the peroxide is covered on additives for polyethylene (PE).

Table T3. Dicumyl peroxide dosage by polymer.

DCP in polyethylene and XLPE cable compounds#

In XLPE cable insulation, dicumyl peroxide is used at 1.4 to 2.0 phr, and a DC-insulation study published in Materials in 2022 found that levels below 1.4 phr failed the hot-set requirement. Across that same band the study measured gel content rising from 74.3 to 81.6 % and hot-set elongation falling from 300 to 80 %, so a pass-fail test rather than cost sets the lower end of the window. The upper end is set by the process: the compound has to survive extrusion at 120 to 140 °C (248 to 284 °F) without starting to cure.

DCP in EVA and POE#

EVA compounds take 2.4 to 4.7 phr of the 40 % dicumyl peroxide formulation, roughly 1.0 to 1.9 phr of active peroxide, while POE and EPDM need 6.1 to 10.1 phr and a coagent. The jump follows from the polymer rather than from the peroxide: the vinyl acetate units of EVA give radicals more abstractable hydrogen than the saturated ethylene-octene backbone of POE. Where the cure has to finish inside a lamination cycle, formulators move to a faster peroxide instead of a higher DCP level; TBEC, laminated near 150 °C (302 °F), is the peroxide used in photovoltaic encapsulant films. Coagents, antioxidants and blowing agents in the same recipe are covered on additives for EVA.

DCP in PEX-a pipe#

PEX-a pipe is made by the Engel process, in which HDPE containing about 2 % peroxide is crosslinked in the melt at 200 to 250 °C (392 to 482 °F). The source for that 2 % figure is secondary and does not specify which peroxide, so the number describes the process rather than a DCP recipe. Our source library names di-tert-butyl peroxide and the hexyne peroxide, not DCP, as the peroxides for PEX-a pipe and crosslinkable rotomoulded polyethylene, because both stay stable at the higher melt temperatures. The three pipe routes and their crosslinking minimums are compared on PEX-a, PEX-b and PEX-c.

How to convert phr of a 40 % DCP formulation into active peroxide#

A 40 % dicumyl peroxide formulation carries 0.4 phr of active peroxide for every 1 phr dosed, so 3.0 phr of Perkadox BC-40 is 1.2 phr of active DCP. Converting that figure to weight percent takes the full formulation total, because phr counts parts per hundred parts of resin and weight percent counts parts of the whole compound: wt% = phr of the ingredient divided by the total phr, times 100. In a compound of 100 phr polyethylene plus 3.0 phr of the 40 % formulation, the active peroxide is 1.2 divided by 103, times 100, which is 1.17 wt%. Peroxide recipes are written in PHR (parts per hundred resin).

What Are the Main Uses of Dicumyl Peroxide? 5 Applications in Plastics#

Dicumyl peroxide is used in 5 main areas: medium- and high-voltage XLPE cable insulation, crosslinked PE and EVA foam, PEX pipe, footwear and rubber goods, and grafting initiation. The 5 areas are listed below.

• Medium- and high-voltage XLPE cable insulation, the largest and most demanding application.
• Crosslinked polyethylene and EVA foam, where the peroxide runs beside a chemical blowing agent.
• PEX pipe and crosslinkable rotomoulded parts.
• Footwear compounds and rubber goods.
• LDPE initiation and grafting, where DCP starts a reaction rather than building a network.

Medium- and high-voltage XLPE cable insulation#

Dicumyl peroxide is the standard crosslinker for medium- and high-voltage XLPE cable insulation, where the compound is extruded at 120 to 140 °C (248 to 284 °F) without starting the cure and then vulcanised above 180 °C (356 °F) for about 5 minutes. Peroxide is one of three routes to crosslinked polyethylene (XLPE), beside silane and electron beam, and the only one that holds the high-voltage end of the market.

Silane crosslinking is unsuitable for high-voltage insulation because the residual water the reaction needs introduces charge carriers into the dielectric, which keeps peroxide XLPE dominant in medium-voltage, high-voltage and HVDC cable.

What the network buys is temperature. A crosslinked cable is rated at 90 to 105 °C (194 to 221 °F) in continuous operation, 130 to 140 °C (266 to 284 °F) in emergency operation and 250 °C (482 °F) for a short circuit of about 0.5 seconds, ratings an uncrosslinked insulation cannot hold. The full insulation package is on additives for wire and cable compounds.

Crosslinked PE and EVA foam#

Crosslinked PE and EVA foam is made by running a blowing agent and a peroxide in the same formulation, so that gas release and crosslinking reach the balance that fixes the foam density. Azodicarbonamide is the blowing agent used, together with DCP or BIPB, and the melt has to gain enough strength to hold the gas before the cells coalesce. Chemically foamed EVA reaches densities of 0.15 to 0.25 g/cm3, and the press window runs from 165 to 190 °C (329 to 374 °F). A published laboratory recipe of 1.35 phr azodicarbonamide with 2 phr zinc oxide and 0.5 to 0.7 phr peroxide uses BIPB, not DCP. Faster peroxides are used where the cure has to finish in a lamination cycle, as explained on crosslinking EVA and POE.

PEX pipe and rotomolded parts#

PEX pipe and crosslinkable rotomoulded tanks are peroxide-crosslinked products in which dicumyl peroxide competes with the more heat-stable di-tert-butyl and hexyne peroxides. Both run their typical crosslink 10 to 15 °C (18 to 27 °F) above the 170 °C (338 °F) of DCP, which matters when the part is crosslinked at 200 to 250 °C (392 to 482 °F) in the Engel process or held for a long cycle in a rotational mould. The pipe then has to meet a minimum degree of crosslinking that differs by route and by standard. Pressure-pipe formulations as a whole are treated on additives for plastic pipes.

Footwear and rubber goods#

Dicumyl peroxide also cures footwear compounds and rubber goods, where the peroxide network gives better compression set and heat resistance than a sulfur cure and does not revert. Footwear midsoles are the largest of those outlets, where a foam that keeps its thickness under repeated loading is what the compression-set advantage buys.

How Much Crosslinking Does Dicumyl Peroxide Deliver?#

Crosslinking is measured as gel content and as hot-set elongation, and dicumyl peroxide at 1.4 to 2.0 phr raised gel content from 74.3 to 81.6 % in a 2022 study of DC cable insulation published in Materials. What counts as enough crosslinking is set by standards rather than by a supplier claim, and the two families of standard disagree with each other. IEC 60811-507 caps hot-set elongation at 175 % for cable insulation, ASTM F876-23 asks PEX tubing for at least 70 % crosslinking by the peroxide route, and DIN 16892 asks 75 % for PE-Xa.

Volatility, extraction and migration behaviour carry no measured value for dicumyl peroxide in our source library, and no electrical value is recorded either, so this page prints no number for them beyond the table below.

Table T4. Crosslinking targets and the standards that set them.

Gel content and hot-set targets for XLPE and PEX#

XLPE cable insulation passes when hot-set elongation stays at or below 175 % under IEC 60811-507, while PEX tubing has to reach 70 % crosslinking by the peroxide route under ASTM F876-23. Gel content measures the insoluble fraction after solvent extraction, hot set measures how far a loaded strip stretches above the crystalline melting point, and the two move in opposite directions as the peroxide level rises.

The standards do not agree, which is why a percentage quoted without its standard means nothing: ASTM F876-23 asks at least 70 % by the peroxide route while DIN 16892 asks 75 % for PE-Xa, and the radiation and silane routes are allowed 65 % in the ASTM text. The routine is described on the gel content and hot set test page.

Peroxide cure versus sulfur cure#

A peroxide cure trades strength for stability: tensile and tear strength are usually about 15 % lower than with a sulfur cure, while compression set and heat resistance improve and the network does not revert. The 15 % figure comes from the Nouryon crosslinking brochure and is a supplier-published typical value. Reversion matters most in thick sections, because a carbon-carbon network does not soften again on overcure as a polysulfidic network does.

How Does DCP Interact with Coagents, Antioxidants and Blowing Agents?#

Dicumyl peroxide is rarely the only reactive ingredient in a compound: coagents raise its crosslink efficiency, blowing agents compete with it for the same processing window, and antioxidants consume radicals before they reach the polymer. Three interactions decide the recipe, and two of them work against the peroxide. TAIC and TMPTMA are crosslinking coagents, and they cut the peroxide dose needed for a given network.

• Coagents, namely triallyl isocyanurate (TAIC) and trimethylolpropane trimethacrylate (TMPTMA), which add reactive unsaturation for the macroradicals to attack.
• Chemical blowing agents, above all azodicarbonamide, which release gas in the cure window.
• Antioxidants and stabilizers, which scavenge radicals and slow the crosslinking reaction.

The coagent figures come from processes other than DCP compounding, so this page names that context. TAIC is the standard coagent in EVA photovoltaic encapsulants and in radiation-crosslinked wire, and TMPTMA raises crosslinking in electron-beam-crosslinked PP and POE foam up to about 8 phr, then plateaus. Azodicarbonamide, the chemical blowing agent for plastics used in crosslinked foam, releases its gas in the peroxide cure window, which is why the two decomposition curves are matched rather than chosen separately.

Antioxidants pull the other way. In a POE and LLDPE silane-grafting study by Dana, Zohuri and colleagues published in 2019, benzoyl peroxide outperformed dicumyl peroxide as the grafting initiator, and 0.3 wt% antioxidant cut the cure time from 14 to 16 hours down to 8 hours. That result belongs to a benzoyl peroxide grafting system, but it shows the size of the interaction a stabilizer package produces.

What Is the Regulatory Status of Dicumyl Peroxide? REACH, CLP and FDA#

Dicumyl peroxide is registered under REACH, has been on the REACH Candidate List since 27 June 2024 as toxic for reproduction, carries a harmonised CLP classification as an organic peroxide and a Category 1B reproductive toxicant, and is not listed in Annex I of Regulation (EU) No 10/2011 (status 24 September 2026). One cell of the matrix below is open rather than negative: the California Proposition 65 entry for DCP is not confirmed in our source library and is marked as being verified.

Table T5. Dicumyl peroxide regulatory matrix, as of 24 September 2026.

Registration, evaluation, the Candidate List and authorisation are four stages of one regulation, and a substance can sit in one without the next. How they fit together is explained on REACH and plastic additives.

Is dicumyl peroxide an SVHC?#

Yes: the European Chemicals Agency added dicumyl peroxide to the REACH Candidate List on 27 June 2024 as a substance toxic for reproduction under Article 57(c), and it was the only entry in that update. The 31st Candidate List update carried that single substance, and ECHA's use description for it reads "processing aid and cross-linker in polymers", which places the listing inside plastics compounding.

Candidate List inclusion is not a ban and not a restriction. It triggers information duties towards customers and towards ECHA, and marks the substance as a candidate for the authorisation list rather than moving it there. The Candidate List held 253 entries on 22 September 2026, and every plastic additive on the SVHC Candidate List is tabulated with its listing date and its Article 57 reason.

What does the SVHC listing mean for XLPE articles, Article 33 and SCIP?#

Once a substance is on the Candidate List, any article containing more than 0.1 % of it by weight carries a REACH Article 33 information duty and has to be notified to the SCIP database. Article 33 obliges the supplier to pass the substance name and safe-use information to professional recipients automatically, and to consumers on request within 45 days.

Whether a finished XLPE cable or an EVA foam exceeds that 0.1 % w/w threshold is a question each compounder answers with its own residual-peroxide data, because our source library records no verified residual figure for cured articles. Articles above the threshold are notified to the SCIP database before they are placed on the EU market, and the measurement, not the dosage, decides.

Is dicumyl peroxide restricted under REACH Annex XVII or listed on Annex XIV?#

Dicumyl peroxide is covered by REACH Annex XVII entries 28 to 30, which keep CMR Category 1A and 1B substances out of mixtures sold to the general public, and it is named in Appendix 6 of those entries by Regulation (EU) 2021/2204. Appendix 6 lists the Category 1B reproductive toxicants that entry 30 catches, the appendices were last updated by Regulation (EU) 2025/1731 of 8 August 2025, and the restriction bites on consumer supply, not on industrial compounding. Entries 28 to 30 and their appendices are explained with the other REACH Annex XVII restrictions.

It is not on Annex XIV, so no authorisation is required to use it, but it sits on the Community rolling action plan (CoRAP) for substance evaluation. Substances that did move from the Candidate List to the REACH Annex XIV authorisation list carry sunset dates; dicumyl peroxide carries none, as of the ECHA CHEM check of 22 September 2026.

Is dicumyl peroxide allowed in food-contact plastics under EU 10/2011 and the FDA rules?#

Dicumyl peroxide is not in the Union list of Annex I to Regulation (EU) No 10/2011, so it is not an authorised additive for EU food-contact plastics. How initiator residues are treated is not settled in our sources, so this page states the Annex I position and no more. The Union list and the rules for substances outside it are set out on EU 10/2011.

In the United States it appears in four food-contact sections of 21 CFR: 175.105 for adhesives, 175.300 as a polymerisation catalyst only, 177.2420 for cross-linked polyester resins and 177.2600 for rubber articles. A fifth section, 21 CFR 177.1810, mentions it only inside a test-procedure note.

None of that is an approval of the substance as such: a 21 CFR listing permits a named use under named conditions, so the four sections sit inside the wider system described on FDA food contact rules for plastic additives, and a compliance statement names the section it relies on.

Is Dicumyl Peroxide Hazardous? CLP Classification, Handling and Environment#

Dicumyl peroxide carries a harmonised classification under the CLP Regulation (Annex VI, index 617-006-00-X, ATP15): Org. Perox. F (H242), Repr. 1B (H360D), Skin Irrit. 2 (H315), Eye Irrit. 2 (H319) and Aquatic Chronic 2 (H411). The classification is harmonised rather than self-assigned, and the signal word is Danger. The three consequences that follow are listed below.

• Classification: heating may cause a fire (H242); it may damage the unborn child (H360D); it causes skin irritation (H315) and serious eye irritation (H319); it is toxic to aquatic life with long-lasting effects (H411).
• Handling: store at or below the Ts max of 30 °C (86 °F), keep the material well below the SADT of 75 °C (167 °F), and keep it away from ignition sources and incompatible materials.
• Environment: the Aquatic Chronic 2 classification (H411) keeps the substance out of drains and surface water; the harmonised entry carries no acute aquatic H400.

The Repr. 1B classification is also the reason for the 2024 Candidate List entry, since Article 57(c) covers reproductive toxicants of Category 1A or 1B. The two classifications drive two sets of duties: a transport and storage regime, and an information and substitution agenda. A harmonised entry binds every supplier in the EU, as explained on CLP classification of plastic additives.

This page is a reference entry, not a safety data sheet: no LD50, NOAEL or occupational exposure limit for dicumyl peroxide sits in our source library, so none is printed here.

What Are the Alternatives to Dicumyl Peroxide?#

The main alternatives to dicumyl peroxide are 4 other crosslinking peroxides (BIPB, DHBP, DTBP and tert-butyl cumyl peroxide) and 2 completely different routes, silane crosslinking and electron-beam crosslinking. The substitution question became live in June 2024: the Candidate List entry pushes formulators to look at the bifunctional peroxides and at the silane and e-beam routes, none of which currently carries a Candidate List entry in the sources checked.

Table T6. Crosslinking peroxides compared.

Footnote: safe processing temperature means a rheometer scorch time ts2 above 20 minutes, and typical crosslinking temperature means a t90 of about 12 minutes; both come from the Nouryon EMEIA crosslinking brochure. Half-life temperatures are measured in dilute chlorobenzene. The Candidate List column reflects the CIRS compilation of the 35th update of November 2025; 2026 updates were not checked.

DCP vs BIPB (Perkadox 14)#

BIPB is the bifunctional alternative: it carries two peroxide groups and 9.45 % active oxygen against DCP's 5.92 %, works 5 °C (9 °F) higher in both the safe-processing and the crosslinking window, and is described by its supplier as the lower-odour option. Its SADT is 80 °C (176 °F) against 75 °C (167 °F) for DCP and its Ts max is the same 30 °C (86 °F), so the storage regime does not change on substitution. BIPB peroxide is the bifunctional dialkyl peroxide most often named as the DCP replacement in EVA foam; our source library marks its byproduct list as unverified, so no claim about which residues it avoids is made here.

DCP vs DHBP (Trigonox 101)#

DHBP is the liquid bifunctional peroxide that crosslinks polyethylene and visbreaks polypropylene, with a 10-hour half-life temperature of 115 °C (239 °F) against 112 °C (233.6 °F) for dicumyl peroxide. It is a clear liquid with a melting range of 1 to 10 °C (33.8 to 50 °F) and a density of 0.872 g/cm3 at 20 °C (68 °F), so it is dosable by pump where DCP is handled as crystals or supported powder. Its active oxygen of 11.02 % is the highest in Table T6, so the delivered weight for a given radical yield is the lowest. DHBP peroxide crosslinks PE and visbreaks PP with the same chemistry, which is why it dominates controlled-rheology polypropylene.

DCP vs DTBP and the high-temperature peroxides#

Di-tert-butyl peroxide sits one step higher on the temperature scale than dicumyl peroxide: its 10-hour half-life temperature is 121 °C (249.8 °F) and its typical crosslinking temperature is 180 °C (356 °F). It is a clear liquid with a boiling point of 110 to 111 °C (230 to 231.8 °F), a flash point of 1 °C (33.8 °F) and 10.94 % active oxygen, so it is volatile and flammable in a way crystalline DCP is not. Above it sit the hexyne peroxide (Trigonox 145) at 145 / 185 °C (293 / 365 °F) and the cyclic Trigonox 311 at 180 / 220 °C (356 / 428 °F). Di-tert-butyl peroxide is the liquid high-temperature member of the same dialkyl class, and it is used for PEX-a pipe.

Where the compound is crosslinked by injecting a liquid peroxide into the extruder, formulators use tert-butyl cumyl peroxide instead of crystalline DCP. tert-Butyl cumyl peroxide (TBCP) runs at the same 135 / 175 °C (275 / 347 °F) window as BIPB and DHBP and is dosed by direct peroxide injection, which removes the powder-handling step from the cable line.

Peroxide, silane and electron-beam crosslinking compared#

Crosslinking does not have to start from a peroxide: the silane route grafts vinyltrimethoxysilane onto the polymer and finishes the network with water, and the radiation route uses an electron beam instead of a chemical initiator. A small peroxide dose grafts vinyltrimethoxysilane onto the polyethylene chain, and the grafted material is crosslinked by water into Si-O-Si bridges, catalysed by dibutyltin dilaurate. The Sioplas two-step version was patented in 1968 and the single-step Monosil version dates from 1974; neither serves high-voltage insulation, because the residual water introduces charge carriers into the dielectric. Silane crosslinking (Sioplas and Monosil) replaces the peroxide network with siloxane bridges.

Electron-beam crosslinking removes the initiator entirely. Effective doses run from 50 to 150 kGy, and in a recycled-polyethylene study gel content rose from 46.7 to 56.2 % between 95 and 125 kGy, with 110 kGy the best balance. The beam works below the crystalline melting point, so the network is less uniform through a thick wall than a melt-phase peroxide cure. Radiation (e-beam) crosslinking needs no initiator at all, which is why it is the PEX-c route.

Who Manufactures Dicumyl Peroxide? Grades and Suppliers#

Dicumyl peroxide is produced by Nouryon, which sells it as Perkadox BC-FF in crystalline form and as the Perkadox BC-40 series of supported and masterbatch grades, and by Arkema under the Luperox line. Nouryon is headquartered in Radnor, Pennsylvania and in Amsterdam, took its present name on 9 October 2018, and runs the Trigonox, Perkadox, Laurox, Expancel, Armostat and Ketjenblack brand lines. Other producers appear in trade listings, but our source library records them as unverified. More producers and certifications are listed in the directory of organic peroxide manufacturers and suppliers.

Table T7. Dicumyl peroxide producers, trade names and grades.

Buyers should ask the supplier for the technical data sheet, the safety data sheet and a statement of the SVHC content of the delivered grade, because the Candidate List entry of 27 June 2024 makes that last document the one a downstream customer asks for first.

Where Does DCP Sit in the Organic Peroxide Family?#

Dicumyl peroxide is the volume leader of the dialkyl peroxides, the sub-class of organic peroxides that crosslink polyolefins rather than initiate polymerisation at low temperature. One secondary compilation puts dialkyl peroxide production at about 60,000 tonnes a year, with DCP the largest single product, and no year is recorded for that figure in our source library. The market it serves stays a specialty inside a commodity: the 2024 ACS Applied Polymer Materials review estimates crosslinked polyolefins at 5 to 10 % of the polyethylene market.

How are crosslinked polyolefins recycled?#

A crosslinked polyolefin cannot be remelted, so recycling it means breaking the network again: pan-milling cut the gel content of peroxide-crosslinked XLPE from 70 to 15 % in one 2024 review of published work. The same review reports pan-milling cutting silane-crosslinked XLPE from 77 to 14 % and supercritical methanol cutting gel content from 88 to 0 %. What happens to the de-crosslinked material afterwards, and which stabilizer package it needs, is covered on additives for recycled plastics.

Dicumyl peroxide outside plastics: rubber vulcanisation#

Outside plastics compounding, dicumyl peroxide is a rubber vulcanising agent, and that market is where most of the older literature on it was written. The peroxide cure competes there with sulfur systems on the same terms as in footwear compounding: about 15 % less tensile and tear strength, better compression set and heat resistance, and no reversion on overcure. The overlap between the two markets is set out on plastic additives in rubber and elastomers.

What is the activation temperature of dicumyl peroxide?#

There is no single activation temperature for dicumyl peroxide: suppliers publish a safe processing temperature of 130 °C (266 °F), at which scorch time stays above 20 minutes, and a typical crosslinking temperature of 170 °C (338 °F), at which 90 % of the cure is reached in about 12 minutes. The two figures bracket the window a compound has to move through, and the half-life triplet of 112, 132 and 154 °C (233.6, 269.6 and 309.2 °F) describes the decomposition rate between them.

What does dicumyl peroxide cost, and where are prices published?#

No verified price for dicumyl peroxide is published in our source library, so this page quotes no figure. Three structural drivers are recorded and do move the delivered cost: the grade form (crystalline at an assay of at least 99 % against a 40 % supported or masterbatch grade), the assay itself, and the order volume. Marketplace listings quote a price per kilogram without naming the grade; where a verified series exists, it is published under plastic additive prices.

Does dicumyl peroxide need an SDS?#

Yes: dicumyl peroxide carries a harmonised CLP classification, so every supplier provides a safety data sheet and a labelled package for it. What an SDS has to contain, and how the CLP label and the transport classification relate to it, is set out on safety data sheets and GHS labels.