Di-Tert-Butyl Peroxide: Properties, Uses in Plastics and Regulatory Status

Di-tert-butyl peroxide (DTBP, CAS 110-05-4) is a liquid dialkyl peroxide used as a high-temperature crosslinking peroxide for polyethylene and as a polymerisation initiator for LDPE and polystyrene. DTBP is chosen where the line runs too hot for dicumyl peroxide, because it is the most heat-stable of the common liquid crosslinking grades, which raises the question of what "too hot" means in numbers.

The Nouryon crosslinking-peroxides brochure for the EMEIA region gives the numbers: a typical crosslinking temperature of 180 °C (356 °F) against 170 °C (338 °F) for dicumyl peroxide, and a safe processing temperature of 145 °C (293 °F) against 130 °C (266 °F). DTBP is registered under REACH and carries a harmonised CLP classification of Flam. Liq. 2 (H225), Org. Perox. E (H242) and Muta. 2 (H341). Crosslinking peroxides are one family among the plastic additives a compounder buys. DTBP is one of 13 crosslinking-agent pages in our directory of plastic additives, each carrying the same identity, dosage and regulatory fields.

This page holds the data sheet and the compliance view in one place: the identity that separates DTBP from tert-butyl hydroperoxide, the homolysis that leaves tert-butanol and acetone in the polymer, the half-life and SADT figures that fix the storage and cure windows, the PEX-a and initiator uses, the comparison against dicumyl peroxide, DHBP, BIPB and hexyne peroxide, a dated regulatory matrix, and the grades a buyer can source.

Table T1. DTBP identity card.

Footnote: identity and physical data from PubChem CID 8033 and the Nouryon Trigonox B product data sheet; regulatory entries from ECHA registration dossier 14549, the ECHA CHEM record 100.003.395 and the legal texts cited in each section. Status as of 22 September 2026.

What Is Di-tert-Butyl Peroxide (DTBP)?#

DTBP is a dialkyl peroxide: two tert-butyl groups joined by a single oxygen-oxygen bond, which is the bond that breaks to start every reaction the additive is used for. DTBP is monofunctional, meaning one oxygen-oxygen bond per molecule and therefore two radicals per molecule, against four for the bifunctional grades DHBP and BIPB. Active oxygen content, the share of the molecular mass that is peroxidic oxygen available to form radicals, is 10.94 % for DTBP, which follows from one peroxide oxygen atom against a molecular weight of 146.23 g/mol. The Nouryon Trigonox B product data sheet describes the commercial liquid as clear colourless to yellow, assay at least 99 %. What makes a peroxide useful inside a polymer at all?

The oxygen-oxygen bond is the weakest bond in the molecule, and heat alone splits it into two radicals without a second reactant. That is what a compounder buys: a molecule stable in a drum at ambient temperature that turns into a radical source at a known rate once the compound reaches cure temperature. Peroxides are one of four routes on the hub for crosslinking agents for polymers, beside silane cures, radiation cures and coagent-assisted cures.

What does DTBP stand for, and what else is abbreviated DTBP?#

DTBP stands for di-tert-butyl peroxide, whose systematic name is 2-tert-butylperoxy-2-methylpropane. In antioxidant literature the same three letters appear as 2,4-DTBP for 2,4-di-tert-butylphenol, a phenol that is a non-intentionally added substance and a degradation product of the phosphite antioxidant Irgafos 168. The two substances share no function: one starts radical reactions on purpose, the other is a breakdown product found in packaging. On this site DTBP alone always means the peroxide, and the phenol is always written 2,4-DTBP with its full name at first mention.

Is di-tert-butyl peroxide the same as tert-butyl hydroperoxide?#

No: di-tert-butyl peroxide (C8H18O2) carries an alkyl group on both sides of the oxygen-oxygen bond, while tert-butyl hydroperoxide carries a hydrogen on one side, and the two behave differently in a polymer. In plastics, hydroperoxide groups are the intermediates that carry polymer oxidation forward, so a formulator works to remove them. A hydroperoxide group in a polymer is normally an oxidation intermediate, not an added crosslinker, which is the opposite of what DTBP is bought for. The 3 substances most often confused separate cleanly on structure.

Which trade names cover di-tert-butyl peroxide?#

The same substance is sold under 3 confirmed names: Nouryon markets it as Trigonox B and as the 30 % solution Trigonox B-C30, and it also appears as Cadox TBP. One further trade name is carried in our reference data with a verification flag against its producer, so it is not printed until the attribution is confirmed on that producer's own literature. Trade names are not specifications: two grades under different names can differ in assay, diluent and maximum storage temperature. Table T8 lists the producers and grade forms our reference data records.

How Does DTBP Crosslink Polyethylene?#

DTBP crosslinks polyethylene by splitting at its oxygen-oxygen bond into two tert-butoxy radicals, which pull hydrogen atoms off the polymer chains so that the resulting macroradicals can combine into carbon-carbon crosslinks. The peroxide is consumed and becomes part of the byproduct set, which is why a crosslinking peroxide is never a catalyst: a catalyst leaves the reaction unchanged, and DTBP does not survive it.

The reaction runs in 3 steps.

1. Homolysis of the oxygen-oxygen bond into two tert-butoxy radicals, driven by heat alone.
2. Hydrogen abstraction from a polyethylene chain, which turns the tert-butoxy radical into tert-butanol and the chain into a macroradical, or beta-cleavage of the same radical into acetone and a methyl radical.
3. Combination of two polymer macroradicals into a carbon-carbon crosslink.

The competition inside step 2 sets the byproduct mix, and both paths end in a radical that can still attack the polymer. The five classes of peroxide and the full cross-grade half-life table sit on organic peroxides for polymers, where the kinetics are treated at family level.

A carbon-carbon crosslink is thermally stable and is not undone by remelting, which is the point of the cure. The same network makes XLPE (crosslinked polyethylene) hold its shape above the crystalline melting point, so a crosslinked pipe keeps its dimensions where uncrosslinked polyethylene would flow. Our reference data records no radical yield, crosslink efficiency or crosslink density for DTBP.

What byproducts does DTBP leave in the polymer?#

DTBP leaves tert-butanol and acetone behind, because its tert-butoxy radicals either take a hydrogen atom from the polymer or split into acetone and a methyl radical. Both byproducts are small, volatile molecules, and both come directly from the two competing paths of step 2 of the cure.

Dicumyl peroxide leaves a heavier set of byproducts, including acetophenone, cumyl alcohol, alpha-methylstyrene, methane and water, which is why high-voltage XLPE insulation is degassed after cure: those residues raise conductivity. No residual-byproduct concentration, degassing time or odour threshold for DTBP sits in our reference data, and the dicumyl peroxide degassing figures are not transferable to a DTBP compound.

Why does DTBP crosslink polyethylene but cut polypropylene?#

The difference is the carbon that loses its hydrogen: polyethylene forms secondary macroradicals that couple, while polypropylene forms tertiary macroradicals that split the chain instead. In polypropylene the tertiary macroradical undergoes beta-scission, so a peroxide visbreaks polypropylene rather than crosslinking it, unless a coagent intercepts the radicals first. Chain scission is the same reaction that runs during polymer degradation, here started deliberately and controlled by dose.

Turning that scission into a product is the subject of peroxide modification of polypropylene, the controlled-rheology route. The published pilot figures belong to DHBP, not to DTBP: in one pilot reactive-extrusion study, 0 to 600 ppm DHBP raised the melt index and narrowed the molecular-weight distribution, and 200 ppm DHBP produced a staple-fibre controlled-rheology polypropylene. No equivalent visbreaking dose for DTBP is recorded in our reference data.

What Are the Physical and Chemical Properties of DTBP?#

DTBP is a clear colourless to yellow liquid with a melting point of -40 °C (-40 °F), a boiling point of 110 to 111 °C (230 to 232 °F) and a flash point of 1 °C (34 °F). The full constant set is below.

Table T2. Physical and chemical properties of di-tert-butyl peroxide.

The flash point and the boiling point decide how the liquid is handled, and both are low for an additive that cures at 180 °C (356 °F): a flash point of 1 °C (34 °F) means an ignitable vapour below normal room temperature, and a boiling point of 110 to 111 °C (230 to 232 °F) means the liquid evaporates readily from an open process. The values above follow the Nouryon Trigonox B product data sheet and PubChem (CID 8033); catalogue listings print a slightly different set, for example a boiling point of 109 to 110 °C (228 to 230 °F) and a flash-point range of 4 to 18 °C (39 to 64 °F), so check which source a data sheet quotes before comparing grades. No vapour pressure, solubility or viscosity value for DTBP sits in our reference data.

Half-life, SADT and the storage temperature of DTBP#

DTBP has a 10-hour half-life temperature of 121 °C (250 °F) in chlorobenzene, the highest of the common liquid crosslinking grades, which is why it survives a hot extruder without curing early. Half-life is the time in which half the peroxide present has decomposed at a stated temperature, quoted in chlorobenzene because that solvent is the supplier method's reference medium. Safe processing temperature means a rheometer scorch time ts2 above 20 minutes, and typical crosslinking temperature means a t90, the time to 90 % of maximum torque, of about 12 minutes.

Table T3. Thermal and kinetic data for DTBP.

SADT, the self-accelerating decomposition temperature, is the lowest temperature at which self-accelerating decomposition may occur in the original packaging, determined by the UN Heat Accumulation Storage Test. The gap between the SADT of 80 °C (176 °F) and the maximum storage temperature of 40 °C (104 °F) is why a peroxide store is temperature-controlled. Half-life at any other temperature follows from the activation energy of 153.46 kJ/mol in the organic peroxide half-life calculator, which applies kd = A multiplied by exp(-Ea/RT) and t½ = ln2/kd.

Which Polymers Use DTBP, and at What Dosage?#

DTBP is used in polyethylene, where it crosslinks finished chains, and in LDPE and polystyrene, where it starts the polymerisation instead. Nouryon lists the grade for PEX-a pipes and tubes, and our foaming and crosslinking dossier names DTBP and hexyne peroxide as the two grades for the high-temperature PEX-a and crosslinkable-rotomolding routes. The polymer list is short for a reason: every entry runs hotter than the dicumyl-peroxide window.

Table T4. Polymers, role and dosage.

No published DTBP dosage range sits in our reference data. The Nouryon recommended-dosage table for crosslinking peroxides covers Trigonox 29, Trigonox 17, Perkadox BC-40, Perkadox 14-40 and Trigonox 101-45, and it does not include Trigonox B, so there is no figure to quote and no defensible way to borrow one from another grade.

Reading such a table needs one conversion. Supplier tables give peroxide levels in PHR (parts per hundred resin) of a diluted formulation, for example phr of a 40 % masterbatch, not in phr of active peroxide, so two numbers that look alike can differ by a factor of 2.5. Record which basis a quoted dosage uses before comparing suppliers.

DTBP in PEX-a pipe (HDPE)#

PEX-a pipe is crosslinked in the melt at 200 to 250 °C (392 to 482 °F), and that temperature is why the route uses the heat-stable grades: DTBP has a typical crosslinking temperature of 180 °C (356 °F), well above dicumyl peroxide's 170 °C (338 °F). The Engel process description in our reference data is generic and does not name the peroxide it assumes, so its peroxide-content figure is not attributed to DTBP on this page.

Degree of crosslinking, also called gel content, is the property the pipe standards set. ASTM F876-23 requires 65 to 89 % overall, with a minimum of 70 % for the peroxide route and 65 % each for the radiation and silane routes. DIN 16892 gives minimums of 75 % for PE-Xa, 65 % for PE-Xb and 60 % for PE-Xc, a set our reference data carries from a secondary source and flags for verification against ISO 15875. How the routes differ is set out on PEX-a, PEX-b and PEX-c.

A pipe compound is more than its peroxide. The rest of the formulation, from antioxidant to carbon black, is on additives for plastic pipes.

DTBP as an LDPE and polystyrene polymerisation initiator#

The same molecule does two jobs: as a polymerisation initiator DTBP starts chain growth from monomer in LDPE and polystyrene production, and as a crosslinking peroxide it joins finished polyethylene chains in a compound. The difference is temporal rather than chemical: an initiator acts when the polymer is made, from monomer, in a reactor, and a crosslinking peroxide acts later, on finished chains, on an extruder or in a mould. Where crosslinking sits in the wider additive package is shown on additives for polyethylene.

No reactor temperature, pressure or initiator concentration for the LDPE or polystyrene process sits in our reference data, so this page describes the role and gives no process numbers. Polystyrene's own additive package is on additives for polystyrene.

Why DTBP is not used in standard rubber compounds#

DTBP is not recommended for standard rubber compounds, because a liquid that boils at 110 °C (230 °F) and flashes at 1 °C (34 °F) evaporates out of an open mixing process before it can cure anything. Which peroxides do work in elastomers is covered under plastic additives in rubber and elastomers, with the general trade-off that a peroxide cure gives tensile and tear strength usually about 15 % lower than a sulfur cure, with better compression set, better heat resistance and no reversion.

What Is DTBP Used For? Applications in Plastics#

DTBP is used in 5 plastics applications: PEX-a pipe and tube, crosslinkable rotomolded polyethylene, LDPE polymerisation, polystyrene polymerisation and crosslinked polyethylene parts processed above the dicumyl-peroxide window. The 5 applications are listed below with the role the peroxide plays in each.

• PEX-a pipe and tube, the highest-temperature of the three PEX routes.
• Crosslinkable rotomolded polyethylene, one of two grades named for the high-temperature route, beside hexyne peroxide.
• LDPE polymerisation, where DTBP is the high-temperature initiator starting chain growth from ethylene.
• Polystyrene polymerisation, the same initiator role from styrene monomer.
• Crosslinked polyethylene parts processed above the dicumyl-peroxide window, where 145 °C (293 °F) safe processing keeps the compound scorch-free on a hot line.

Crosslinkable rotomolded tanks are one of the two high-temperature routes described on additives for rotational molding, where the peroxide has to survive a long heating cycle in an open mould. Foam, EVA solar encapsulant and medical crosslinking belong in our reference data to dicumyl peroxide, BIPB and TBEC, not to DTBP.

Cable insulation is dicumyl-peroxide territory rather than DTBP territory, and that insulation package is on additives for wire and cable compounds.

How Does DTBP Compare with Other Crosslinking Peroxides?#

On the two numbers that decide grade choice, DTBP sits near the top of the range: a 10-hour half-life temperature of 121 °C (250 °F) and a safe processing temperature of 145 °C (293 °F), against 112 °C (234 °F) and 130 °C (266 °F) for dicumyl peroxide. The eight grades our reference data carries are compared below on half-life, process window, active oxygen and typical use.

Table T5. Crosslinking peroxide comparison.

Footnote: half-life values are measured in chlorobenzene. Safe processing temperature means a rheometer ts2 above 20 minutes; typical crosslinking temperature means a t90 of about 12 minutes. Both sets come from Nouryon product literature.

A high process window buys speed and costs heat. A safe processing temperature of 145 °C (293 °F) means the compound can be mixed and shaped on a hotter, faster line without scorch, which is premature crosslinking in the extruder; the same chemistry means the part has to reach 180 °C (356 °F) before it cures at all. Two grades sit above DTBP: hexyne peroxide at 145 °C processing and 185 °C (365 °F) cure, and Trigonox 311 at 180 °C (356 °F) processing and 220 °C (428 °F) cure. Active oxygen sets how much radical mass a kilogram of peroxide delivers, and at 10.94 % DTBP carries nearly twice that of dicumyl peroxide at 5.92 %. No scorch time, gel content, crosslink density, tensile value or hot-set value for a DTBP compound sits in our reference data, so this comparison names those metrics without DTBP numbers against them.

How Does DTBP Interact with Coagents and Other Additives?#

A coagent is added with a peroxide to raise crosslink efficiency, hold back chain scission and cut the peroxide dose, and the coagents used with dialkyl peroxides fall into 2 types. Both give the radicals a fast, reactive target that ends in a network junction rather than a cut chain.

• Type II coagents, the allylic ones: triallyl isocyanurate (TAIC) and triallyl cyanurate (TAC).
• Type I coagents, the acrylate, methacrylate and maleimide ones: trimethylolpropane trimethacrylate (TMPTMA), ethylene glycol dimethacrylate (EGDMA) and N,N'-m-phenylene dimaleimide (CAS 3006-93-7).

Type I and Type II are compared on crosslinking coagents, where the two mechanisms and their effect on scorch are set out side by side. The quantitative coagent data our reference base holds comes from a radiation study: in electron-beam crosslinked polypropylene and polyolefin-elastomer foam, TMPTMA can raise the degree of crosslinking up to about 8 phr of coagent and then plateaus, with a maximum of 55 % crosslinking at 15 kGy.

The standard Type II allylic coagent is TAIC (triallyl isocyanurate).

Radiation-crosslinked foam uses the Type I coagent TMPTMA. No DTBP-plus-coagent ratio, no antioxidant-interference figure and no filler-interaction datum for DTBP sits in our reference data, so none is stated here, however plausible an interaction may sound.

What Is the Regulatory Status of DTBP?#

DTBP is registered under REACH, is not a Substance of Very High Concern, carries a harmonised CLP classification that includes Muta. 2, sits on the CoRAP evaluation list and is listed on the US TSCA inventory (status 22 September 2026). The instrument-by-instrument position is below.

Table T6. Regulatory matrix for DTBP, as of 22 September 2026.

What registration, evaluation and the Candidate List mean for an additive is explained on REACH, which also sets out why a CoRAP entry is an evaluation step rather than a restriction: a substance on CoRAP has been selected by a Member State for substance evaluation, and the outcome can be a data request, a harmonised-classification proposal, a restriction proposal or no action.

US inventory status and risk evaluations are tracked on TSCA. An inventory listing means the substance may be manufactured or imported in the United States, and says nothing about its use in a finished article.

Is DTBP REACH registered, and is it an SVHC?#

Yes, DTBP is registered under REACH, and no, it is not a Substance of Very High Concern: it is absent from the Candidate List, although it does sit on the CoRAP evaluation list. The registration is ECHA dossier 14549, and it is active.

The commercial weight of that answer comes from the contrast with the grade DTBP is measured against. Dicumyl peroxide joined the SVHC Candidate List on 27 June 2024 as toxic for reproduction under Article 57(c) of REACH, and residual dicumyl peroxide above 0.1 % w/w in an article triggers REACH Article 33 communication and a SCIP notification to ECHA.

That listing of dicumyl peroxide is the biggest single reason formulators are reviewing their peroxide choice.

Is DTBP allowed in food-contact plastics?#

DTBP is not in the Union list of Regulation (EU) No 10/2011, which is the normal position for a polymerisation initiator: aids to polymerisation that are not on the list may still be present in a plastic layer under Article 6(4)(b), with national law applying. Our reference data marks that reading of Article 6(4)(b) as an interpretation rather than a cited ruling, so it is stated with the qualifier and not as a clearance. The Union list is explained on EU 10/2011.

In the United States, DTBP appears in 21 CFR 177.2600 for rubber articles intended for repeated use, and among the substances named in 21 CFR 177.1210 for closure-sealing gaskets. Neither citation is a general food-contact clearance for plastics: both are use-specific sections with their own conditions. Which 21 CFR part applies to which use is set out under FDA food contact rules for plastic additives.

Is DTBP listed under California Proposition 65?#

No Proposition 65 listing for CAS 110-05-4 is recorded in our reference data as of 22 September 2026, and that absence of a record is not established as a verified negative against the current OEHHA list. Listing dates for every additive are on California Proposition 65; a formulator selling into California checks the current OEHHA list for the exact CAS number before relying on a negative.

Is DTBP Safe? Hazard Classification, Handling and Storage#

DTBP carries a harmonised EU classification under CLP Annex VI (index 617-001-00-2, ATP03): Flam. Liq. 2 (H225), Org. Perox. E (H242) and Muta. 2 (H341), so it is regulated as both a highly flammable liquid and an organic peroxide. A harmonised classification is set in the legal text of Regulation (EC) No 1272/2008 rather than self-assigned, so every EU supplier classifies the substance the same way. The 3 operational consequences are listed below.

• Classification: Flam. Liq. 2 (H225, highly flammable liquid and vapour), Org. Perox. E (H242, heating may cause a fire) and Muta. 2 (H341, suspected of causing genetic defects).
• Storage: a maximum storage temperature of 40 °C (104 °F) against an SADT of 80 °C (176 °F) in the original packaging, which makes temperature-controlled storage part of the specification rather than an option.
• Handling: organic peroxides are class 5.2 dangerous goods; never weigh out peroxide in the storage room, keep peroxides away from reducing agents such as amines, and melt frozen liquid peroxides only by indirect heating at about 25 °C (77 °F) maximum.

A flash point of 1 °C (34 °F) means the liquid gives off an ignitable vapour at ordinary room temperature, so ignition sources, not only heat sources, govern the handling procedure. What each hazard statement means on a label is explained under safety data sheets and GHS labels, which sets out the H-codes, the pictograms and the CLP and OSHA HazCom sections.

The Muta. 2 entry decides how the substance is treated in a hazard review. Category 2 under CLP means suspected of causing genetic defects, assigned on limited evidence, and it is not a proven-carcinogen listing; how the categories differ is explained on toxic plastic additives. Compounders should follow the supplier's safety data sheet for storage temperature, incompatible materials and fire response. No LD50, LC50, NOAEL, occupational exposure limit, UN number or packing group for DTBP sits in our reference data.

What Are the Alternatives to DTBP?#

The 5 main alternatives to DTBP are dicumyl peroxide, DHBP, BIPB, hexyne peroxide and Trigonox 311 among the peroxides, plus two routes that use no peroxide at all: silane crosslinking and electron-beam crosslinking. Each is chosen for a different reason, and the table records which one.

Table T7. Alternatives to DTBP.

All five classes of organic peroxides used in polymers, the dialkyl, peroxyketal, peroxycarbonate, cyclic and diacyl families, are compared on the class page. The 4 comparisons below take the grades a DTBP buyer chooses between.

DTBP vs dicumyl peroxide (DCP)#

DTBP is the better choice when the line runs hot: its safe processing temperature is 145 °C (293 °F) against 130 °C (266 °F) for dicumyl peroxide, and it is not on the SVHC Candidate List, which DCP joined on 27 June 2024. The other 3 numbers run the same way: a 10-hour half-life temperature of 121 °C (250 °F) against 112 °C (234 °F), a typical crosslinking temperature of 180 °C (356 °F) against 170 °C (338 °F), and an active oxygen content of 10.94 % against 5.92 %. The byproduct sets differ too: DTBP leaves tert-butanol and acetone, DCP leaves acetophenone, cumyl alcohol, alpha-methylstyrene, methane and water.

DCP keeps real ground all the same. Dicumyl peroxide (DCP) is a solid with a 130 °C safe processing temperature, easier to dose and store than a liquid with a 1 °C (34 °F) flash point; it is the established cable and foam grade; and its dosage tables are published, which DTBP's are not.

DTBP vs hexyne peroxide and Trigonox 311#

Hexyne peroxide shares DTBP's 145 °C (293 °F) safe processing temperature but cures 5 °C higher, at 185 °C (365 °F), and Trigonox 311 sits far above both, at 180 °C (356 °F) processing and 220 °C (428 °F) cure. Hexyne peroxide, CAS 1068-27-5, is a bifunctional acetylenic dialkyl peroxide with an active oxygen content of 11.17 %, supplied at 85 % in mineral oil and used for PEX and crosslinked rotomolding, the same application pair DTBP serves.

That grade, DHBP-3 (hexyne) peroxide, cures 5 °C above DTBP, so the choice turns on how much heat the line can put into the part. Trigonox 311, 3,3,5,7,7-pentamethyl-1,2,4-trioxepane, CAS 215877-64-8, is a different substance from Trigonox 301.

The cyclic grade Trigonox 301 (cyclic triperoxonane), CAS 24748-23-0, cuts polypropylene rather than crosslinking it, and its active oxygen content of 18.16 % is the highest in Table T5.

DTBP vs DHBP and BIPB#

DHBP and BIPB are bifunctional: each molecule carries two oxygen-oxygen bonds and can release four radicals, against two for the monofunctional DTBP. Both cure in the same window, 135 °C (275 °F) safe processing and 175 °C (347 °F) typical crosslinking, one step below DTBP on processing and 5 °C below it on cure.

The first of the pair, DHBP peroxide, CAS 78-63-7, C16H34O4, 290.44 g/mol, has a 10-hour half-life temperature of 115 °C (239 °F) in chlorobenzene and an active oxygen content of 11.02 %, and is allowed by FDA 21 CFR 177.1520 as an initiator for propylene polymers with residual tert-butyl alcohol at or below 100 ppm.

Cable compounders reach instead for BIPB peroxide, CAS 25155-25-3 for the isomer mixture and 2212-81-9 for the 1,3-isomer, because of its cleaner byproduct profile, at an active oxygen content of 9.45 %.

The liquid cable grade of the same window is tert-butyl cumyl peroxide (TBCP), CAS 3457-61-2.

Silane and electron-beam crosslinking as non-peroxide routes#

Two routes reach the same network without a crosslinking peroxide: silane crosslinking, which grafts vinyltrimethoxysilane onto the polymer and then cures it with water, and electron-beam crosslinking, which uses radiation at 50 to 150 kGy and no chemical at all. Silane crosslinking still uses a small peroxide dose for the grafting step, but the network itself forms later, by moisture.

The grafted polymer is shaped first and crosslinked afterwards, when water hydrolyses the methoxy groups and condensation joins them into silicon-oxygen-silicon bridges with a condensation catalyst such as dibutyltin dilaurate. The two industrial variants are compared on silane crosslinking (Sioplas and Monosil): the two-step route was patented in 1968 and the single-step route dates from 1974. Silane XLPE is unsuitable for high-voltage insulation, because residual water adds charge carriers.

The grafted monomer that makes the water cure possible is vinyltrimethoxysilane (VTMS).

Dose windows for radiation (e-beam) crosslinking are covered separately; the effective range for polyethylene is 50 to 150 kGy, the PEX-c route.

Who Manufactures DTBP? Grades and Suppliers#

DTBP is made by Nouryon, which sells it as Trigonox B and as the 30 % solution Trigonox B-C30, and by Arkema. Our reference data carries a further producer entry with a verification flag, unprinted until that company's own product literature confirms it, so the table below records what is verified rather than the whole market.

Table T8. DTBP grades and suppliers.

Footnote: grade lists are the ones carried in our reference data as of 22 September 2026 and are not a complete product range; ask each supplier for its current portfolio.

More producers and their locations are in the directory of organic peroxide manufacturers and suppliers. Buyers should ask for the assay, the diluent, the maximum storage temperature and the safety data sheet with every quotation, because a 30 % solution and a 99 % liquid are dosed and stored differently even though both are sold as DTBP. No price, tonnage or market share for DTBP sits in our reference data.

Where Does DTBP Sit in the Organic Peroxide Family?#

DTBP is the most heat-stable liquid member of the dialkyl peroxides, the class that also holds dicumyl peroxide, DHBP, BIPB, TBCP and hexyne peroxide and that carries almost all polyolefin crosslinking. The radical crosslinker taxonomy has four neighbouring routes: peroxide cures, coagent-assisted cures, silane cures and radiation cures, with peroxide modification of polypropylene as the scission counterpart of the same chemistry. Where each route fits is summarised on the hub for crosslinking agents.

Dialkyl peroxides: the class DTBP belongs to#

Dialkyl peroxides are the largest of the 5 peroxide classes used in polymers, and their production is reported at about 60,000 tonnes per year, with dicumyl peroxide taking the largest share. The tonnage figure is reported by a secondary source citing Ullmann's Encyclopedia of Industrial Chemistry, and it covers the class as a whole. No DTBP-specific tonnage exists in our reference data, so the 60,000 tonne figure is not split by grade.

The other 4 classes are peroxyketals, peroxycarbonates, cyclic peroxides and diacyl peroxides, each with its own decomposition band. Trigonox 117 (TBEC) is the peroxycarbonate of Table T5, and Trigonox 301 is the cyclic grade.

How large is the crosslinked-polyolefin market?#

Crosslinked polyethylene is a small but growing slice of the polyethylene market: XLPE and PEX together account for roughly 5 to 10 % of it, with a compound annual growth rate of 6 to 8 % expected. Pipe, cable insulation and foam are the three volume outlets, and the pipe share is the one that carries the high-temperature peroxides.

Segment sizes across every additive family are on plastic additives market. No peroxide-level split sits in our reference data, so the 5 to 10 % share is stated for crosslinked polyolefins as a whole and not for any single grade.

Is di-tert-butyl peroxide flammable?#

Yes: DTBP is classified Flam. Liq. 2 (H225) and has a flash point of 1 °C (34 °F), so it gives off an ignitable vapour at ordinary room temperature. It also carries Org. Perox. E (H242), heating may cause a fire, which is a separate hazard from flammability and governs the storage temperature rather than the ignition sources.

Is DTBP the same as Trigonox B?#

Trigonox B is Nouryon's trade name for di-tert-butyl peroxide, so the two names describe the same substance, CAS 110-05-4; Trigonox B-C30 is the same peroxide supplied as a 30 % solution. A trade name identifies a supplier's grade, including its assay and diluent, while the CAS number identifies the substance itself.

Can DTBP crosslink PVC or polypropylene?#

No: peroxides cut polypropylene chains instead of joining them, and PVC is not peroxide-crosslinked in any of its core applications. Polypropylene forms tertiary macroradicals that undergo beta-scission, which is the basis of controlled-rheology polypropylene rather than of a cure. PVC reaches its properties through plasticizers, heat stabilizers and processing aids, and its core applications use no peroxide crosslinking step.

Does DTBP need a safety data sheet?#

Yes: DTBP carries a harmonised CLP classification and is supplied with a safety data sheet, which is the document that states its storage temperature and its incompatible materials. A harmonised entry under Regulation (EC) No 1272/2008 makes the hazard section of that sheet the same across suppliers, while the storage, handling and emergency sections stay supplier-specific and grade-specific.