Azodicarbonamide (ADCA): Chemical Blowing Agent for Plastics, Properties and Regulatory Status

Azodicarbonamide (ADC or ADCA, CAS 123-77-3) is an exothermic chemical blowing agent that decomposes at about 200 to 210 °C (392 to 410 °F) and releases 200 to 220 mL of gas per gram, mostly nitrogen, to foam PVC, EVA and polyethylene. Because that decomposition point sits above the fusion range of a PVC plastisol, the first question a formulator asks is how activators move it down. Its systematic name is diazene-1,2-dicarboxamide, its molecular formula C2H4N4O2 and its molecular weight 116.08 g/mol.

Azodicarbonamide has been on the REACH Candidate List of substances of very high concern since 19 December 2012 for its respiratory sensitising properties, carries the harmonised CLP classification Resp. Sens. 1 with hazard statement H334, has been suspended as a blowing agent in EU plastic food-contact materials since 2 August 2005 under Commission Directive 2004/1/EC, and is allowed in the United States at up to 5 % of the finished foamed polyethylene under 21 CFR 178.3010. Azodicarbonamide is the highest-volume chemical blowing agent in our directory of plastic additives, each entry carrying the same identity, dosage and regulatory fields.

What follows runs in the order a formulator meets the substance: identity, the azo-bond decomposition and its 4 gases, the kickers that pull the onset from 210 °C to 140 °C, the physical constants, the dose per polymer against the regulatory ceilings, the 6 applications, the performance against OBSH and bicarbonate, the formulation partners, the dated regulatory matrix, the handling classification, the 6 alternative routes and the producers.

The identity table below collects the numbers that identify azodicarbonamide in a specification and a compliance declaration.

Table T1. Azodicarbonamide identity at a glance.

What Is Azodicarbonamide (ADCA), and Why Is It a Chemical Blowing Agent?#

Azodicarbonamide is an azo compound, diazene-1,2-dicarboxamide, in which two amide groups sit on either side of a nitrogen-nitrogen double bond that breaks on heating and releases the gas that blows the foam. That azo group, written N=N, is thermally weaker than the carbon-nitrogen and carbon-oxygen bonds around it, so a single heating step converts a stable yellow to orange powder into a large volume of permanent gas at a temperature a polymer processor already reaches.

What makes an azo compound useful as a blowing agent rather than as a dye? A chemical blowing agent is a substance that decomposes or reacts on heating and releases gas that forms a cellular structure in a polymer, and azo dyes keep their N=N bond inside a conjugated aromatic system while azodicarbonamide carries it between two small amide groups that give it up. Azodicarbonamide is the reference member of the chemical blowing agents, the group that releases its gas by decomposing rather than by boiling, and the foam review by Rostami-Tapeh-Esmaeil and Rodrigue (Polymers, 2021, article 1565) names it as one of 6 main organic types alongside TSSC, 5-phenyltetrazole, OBSH, DPT and the isocyanate and water system.

What does ADCA stand for, and is ADC the same as ADA?#

ADCA stands for azodicarbonamide, and ADC, AC and ADA name the same substance, CAS 123-77-3: ADC and ADCA in the plastics trade, AC (as in AC foaming agent) in Chinese and Indian supply, and ADA in US Food and Drug Administration documents. The chemical literature adds azodicarboxamide, azobisformamide, azodiformamide and 1,1'-azobisformamide, while ECHA registers the substance as C,C'-azodi(formamide). A purchase order that says AC blowing agent, an FDA docket that says ADA and a European safety data sheet that says C,C'-azodi(formamide) all describe one CAS number.

Why is azodicarbonamide called the yoga mat chemical?#

Azodicarbonamide picked up the press nickname yoga mat chemical because the same blowing agent foams PVC yoga mats and, in flour treatment, once appeared on bread labels in the United States. The nickname is a media term rather than a technical one, and it names a shared substance rather than a shared exposure. In a cured foam the additive has already decomposed into gas and solid residues.

The two uses answer to two separate regulatory regimes: the plastics side to Regulation (EU) No 10/2011 and Commission Directive 2004/1/EC, the flour side to 21 CFR 172.806. Flour treatment falls outside this reference and is demarcated in one supplementary section at the foot of the page.

How Does Azodicarbonamide Work as a Blowing Agent?#

Azodicarbonamide foams a plastic by thermal decomposition: the nitrogen-nitrogen bond breaks above about 200 °C (392 °F), the released gas expands the softened melt into closed cells, and the solid residue stays in the polymer. The reaction is exothermic, so once it starts it supplies part of the heat for its own continuation, and the review value for its activation energy is 182 kJ/mol against 79 kJ/mol for a typical rubber curing reaction (Rostami-Tapeh-Esmaeil and Rodrigue, Polymers, 2021). That energy barrier keeps the powder stable in the feed throat while still allowing a fast, complete release inside the barrel or the oven.

Does the melt hold that gas? Only if melt strength rises as the gas appears, which is why crosslinked polyolefin foam runs a peroxide and a blowing agent in the same formulation, and why a linear polyethylene of the wrong grade collapses into open, coalesced cells. Chemical, physical and particle-form blowing agents are compared side by side on the family hub, where the same melt-strength argument sets the boundary between the chemical and the physical route.

Which gases does azodicarbonamide release?#

Azodicarbonamide releases 4 gases: nitrogen, which dominates the mixture, plus carbon monoxide, carbon dioxide and ammonia. The 4 gases and their roles in the foam are listed below.

• Nitrogen. The dominant species by volume, chemically inert, and the reason the gas stays in the cell.
• Carbon monoxide. A minor decomposition gas that leaves with the extraction air on a foaming line.
• Carbon dioxide. A minor species in the neat decomposition, which one surface-activation route promotes.
• Ammonia. A minor species that carries the characteristic odour of an azodicarbonamide foaming line.

The proportions move with the activation chemistry. In one rotational polyethylene foaming study (ACS Omega, 2024), an ammonium dihydrogen phosphate surface activator shifted the main gas from ammonia to carbon dioxide and lowered the onset from about 210 °C (410 °F) to about 180 °C (356 °F).

What solid residues does azodicarbonamide leave?#

Azodicarbonamide leaves 3 solid residues in the foam, biurea, urazole and cyanuric acid, and forms semicarbazide as a secondary product. The 3 residues remain dispersed in the polymer after the gas has expanded the cells.

• Biurea. The principal solid residue, a high-melting white powder that stays dispersed in the foam.
• Urazole. A cyclic residue formed in parallel with biurea along the same decomposition pathway.
• Cyanuric acid. A thermally stable triazine residue of the same decomposition.

Semicarbazide carries the regulatory weight. Its formation is the stated reason the European Commission suspended the use of azodicarbonamide as a blowing agent in plastic food-contact materials, with effect from 2 August 2005. No residue quantity and no migration value is held in our source library.

How do kickers such as zinc oxide and zinc stearate lower the decomposition temperature?#

Kickers lower the decomposition onset of azodicarbonamide from about 210 °C (410 °F) to 140 to 165 °C (284 to 329 °F), which is what brings it inside the fusion range of a PVC plastisol. Zinc oxide, zinc stearate and urea are the standard blowing agent activators (kickers) for azodicarbonamide. The 3 activator families in commercial use are listed below.

• Metal oxides. Zinc oxide is the classic kicker, and ECHA holds a registered reaction mass of C,C'-azodi(formamide) and zinc oxide under EC number 907-545-1, a pre-activated azodicarbonamide.
• Metal soaps. Zinc stearate acts as kicker and lubricant at once.
• Amides and amines. Urea and its derivatives form the non-metallic family, used where a metal residue is unwanted.

Gas yield falls as the onset falls, and that trade-off is the selection rule. Eiwa Vinyfor DW#6 decomposes at 165 °C (329 °F) and still gives 210 mL/g, SE#30 at 142 °C (288 °F) gives 140 mL/g, and FE-788 at 140 °C (284 °F) gives only 135 mL/g. Zinc oxide carries its own food-contact identity as FCM substance 402 under the zinc migration limit of 5 mg/kg in Annex II of Regulation (EU) No 10/2011.

Why is azodicarbonamide decomposition exothermic, and when does it scorch a part?#

Azodicarbonamide decomposition releases 1.36 kJ of heat per gram, measured by differential scanning calorimetry between 160 and 230 °C (320 and 446 °F), and that heat accumulates in thick sections. The heat accumulates because a polymer conducts heat poorly: gas generation in the core raises the local temperature, the higher temperature accelerates the remaining decomposition, and the cycle can run faster than the section sheds heat. A part that runs away in this manner can scorch, showing a discoloured or degraded core while the skin still looks correct.

What Are the Physical and Chemical Properties of Azodicarbonamide?#

Azodicarbonamide is a yellow to orange powder with a density of 1.65 g/cm3 at 20 °C (68 °F) that does not melt: it decomposes, which PubChem records as 225 °C (437 °F) with decomposition. It is insoluble in water and in common organic solvents and dissolves only in dimethyl sulfoxide, so it disperses in a polymer as a solid particle, and particle size governs how evenly the gas appears.

Table T2. Physical and chemical properties of azodicarbonamide.

Three decomposition figures circulate for one substance, each correct inside its own frame: 225 °C (437 °F) with decomposition is the PubChem value for the pure compound, about 210 °C (410 °F) the pure-substance value in the Rostami-Tapeh-Esmaeil and Rodrigue review, and 200 to 209 °C (392 to 408 °F) the range Eiwa Chemical publishes for its standard Vinyfor grades. A formulator who needs a process window compares grade data sheets, not encyclopedia entries.

What is the decomposition temperature of azodicarbonamide, and how is it measured by DSC?#

Standard azodicarbonamide grades decompose at 200 to 209 °C (392 to 408 °F), the pure substance at about 210 °C (410 °F), and activated grades at 140 to 165 °C (284 to 329 °F). Blends of azodicarbonamide with OBSH, sold by Eiwa Chemical as Spangcell, fill the gap between those two bands at 150 to 185 °C (302 to 365 °F), and a masterbatch keeps the decomposition point of the powder it carries. The grade table below is the working version of that spread.

Table T3. Decomposition window and gas yield by azodicarbonamide grade type.

Grade values are representative supplier figures, not specifications. Ask for the current grade data sheet.

The decomposition point and the 1.36 kJ/g decomposition energy both come from DSC testing for plastic additives, which is why supplier values shift with heating rate. A differential scanning calorimetry scan records the onset, the peak and the integrated heat of the exotherm, and a faster ramp pushes the recorded onset upward.

How much gas does one gram of azodicarbonamide release?#

One gram of standard azodicarbonamide releases 200 to 220 mL of gas measured at 0 °C (32 °F) and 1 atm, and a rubber-foam review by Rostami-Tapeh-Esmaeil and Rodrigue (Polymers, 2021) puts the pure substance at 231 cm3/g. Activated grades give less, from 210 mL/g at a 165 °C (329 °F) onset down to 135 mL/g at 140 °C (284 °F), because part of the molecule is consumed along the lower-energy route the kicker opens.

Against OBSH at 120 to 125 mL/g, azodicarbonamide delivers roughly twice the gas per gram, which is why it remains the volume standard for low-density foam.

Which Polymers Use Azodicarbonamide, and at What Dosage in PHR?#

Azodicarbonamide is dosed in parts per hundred resin, and the published numbers split into two kinds: technical formulations such as 1.35 phr in a crosslinked EVA midsole, and regulatory ceilings such as the 5 wt% of finished foamed polyethylene allowed by 21 CFR 178.3010. Why is a regulatory ceiling not a recommended dose? The ceiling is the maximum a food-contact rule tolerates in the finished article, not the level that reaches the target density, and a formulation that runs at the ceiling is a formulation that has gone wrong.

Foam recipes give azodicarbonamide in PHR (parts per hundred resin), which converts to weight percent against the full formulation total, so the two units are never interchangeable inside a compliance document. Across all blowing agents and all foamed plastics, the composition range is 0.05 to 20 wt% of the finished product, a figure tabulated by Chea and co-workers in 2025 from the additive review of Hahladakis and colleagues (Journal of Hazardous Materials, 2018).

Table T4. Azodicarbonamide dosage by polymer and process.

Azodicarbonamide in PVC foam: plastisol, calendered and extruded#

PVC is the classic host for azodicarbonamide: cushion vinyl, wallpaper and artificial leather are foamed with activated grades whose decomposition point has been pulled down to 140 to 165 °C (284 to 329 °F), inside the fusion range of a plastisol. PVC is not peroxide-crosslinked in these core applications, so the melt strength that holds the gas comes from the fusion state of the resin and its plasticizer system rather than from a crosslinker. The rest of the cushion-vinyl recipe, stabilizer, plasticizer and filler, is set out under additives for PVC.

No verified azodicarbonamide dose for PVC is held in our source library, and this page prints none. The loading comes from the grade data sheet of the activated powder specified, because the gas volume of that grade, not of the generic substance, sets the level. Grade selection for cushion vinyl and Celuka board is compared on blowing agents for PVC foam.

Azodicarbonamide and BIPB peroxide in EVA and crosslinked polyolefin foam#

Crosslinked EVA foam runs azodicarbonamide and a peroxide in the same formulation: a laboratory midsole recipe uses 1.35 phr of azodicarbonamide with 2 phr of zinc oxide and 0.5 to 0.7 phr of BIPB, pressed at 165 to 190 °C (329 to 374 °F). BIPB peroxide builds the melt strength that lets the EVA hold the gas, and in one study the gel content reached 78 % at 0.7 phr and 91 % at 1.2 phr. The zinc oxide serves twice over, as the kicker that drops the azodicarbonamide onset into the press window and as the activator of the crosslinking system.

The pairing decides the achievable density. In the same study, chemical foaming reached 0.15 to 0.25 g/cm3 inside a narrow 170 to 190 °C (338 to 374 °F) window, while physical foaming with nitrogen at 15 MPa reached 0.13 g/cm3 across a wider 80 to 180 °C (176 to 356 °F) window. The full midsole package is on additives for EVA.

Azodicarbonamide masterbatch for injection molding and extrusion#

Injection molders buy azodicarbonamide as a masterbatch rather than as a powder: Eiwa Panthlene H7351 carries 70 % azodicarbonamide in a polyethylene carrier with a decomposition point of 200 °C (392 °F). The same producer offers Polythlene EB106 as an ABS-carrier masterbatch, which matches the carrier to the host polymer. A pellet concentrate also removes airborne powder from the dosing station, which matters for a substance classified as a respiratory sensitiser.

Carrier resins, active contents and dosing for foaming agent masterbatch are covered separately. No let-down ratio for an azodicarbonamide masterbatch is held in our source library, so the ratio comes from the supplier sheet and the target density, calculated on active content. Avient reports 10 to 20 % less plastic with chemical foaming agents in injection molding, including a 20 % weight reduction on a car dashboard, both supplier claims.

What Is Azodicarbonamide Used For? 6 Applications in Plastics#

Azodicarbonamide is used in 6 plastics applications: cushion vinyl flooring, wallpaper, artificial leather, EVA and polyethylene foam for footwear and mats, crosslinked polyolefin foam sheet, and injection-molded structural foam, plus closure gaskets in the United States. They are listed below in order of volume.

• Cushion vinyl flooring and PVC wallpaper. Foamed PVC layers that carry the embossing and the underfoot cushioning.
• Artificial leather. A foamed PVC interlayer between a fabric backing and a skin coat.
• Footwear midsoles, exercise mats and carpet underlay. Crosslinked EVA and polyethylene foam.
• Crosslinked polyolefin foam sheet. Peroxide or electron-beam crosslinked PE, PP and POE sheet.
• Injection-molded structural foam. Thick-walled parts moulded with a foaming masterbatch.
• Closure-sealing gaskets. Cap and closure liners, the one US food-contact use with its own explicit ceiling.

How these applications sit inside the wider foam market is covered under additives for plastic foams.

Cushion vinyl flooring and wallpaper#

Cushion vinyl flooring and PVC wallpaper are the largest azodicarbonamide applications: a foamable layer containing an activated grade is gelled and then expanded, which gives the wear layer its cushioning. The activated grade matters because expansion has to happen inside the fusion range of the PVC layer, at 140 to 165 °C (284 to 329 °F) rather than at 208 °C (406 °F).

Neither the EU food-contact suspension of 2 August 2005 nor the REACH Candidate List entry of 19 December 2012 removes azodicarbonamide from flooring or wall covering, because the suspension applies to plastic food-contact materials and the Candidate List entry creates communication duties above 0.1 % w/w rather than a use ban.

Artificial leather#

Artificial leather uses azodicarbonamide in the foamed PVC interlayer that sits between the fabric backing and the skin coat, where the cell structure produces the softness and the drape. The construction is a sandwich: a woven or non-woven backing carries a foamable plastisol layer, and a compact skin layer on top takes the grain embossing. The blowing agent works only in the middle layer, so the skin stays dense enough to be printed and abraded.

No dosage, density or cell-size value for artificial leather is held in our source library, so this page describes the construction without quantifying it.

Footwear midsoles, mats and carpet underlay#

Footwear midsoles, exercise mats and carpet underlay are made from crosslinked EVA and polyethylene foam blown with azodicarbonamide, and chemically foamed EVA lands at 0.15 to 0.25 g/cm3. These three products share one requirement, a closed-cell structure that recovers after compression, and the midsole is the demanding case because it is cycled continuously in use.

In the EVA foam study behind the 1.35 phr formulation, physical foaming with nitrogen at 15 MPa reached 0.13 g/cm3 against 0.15 to 0.25 g/cm3 on the chemical route, so the physical route reaches a lower density while the chemical route works with ordinary press equipment. That equipment argument is why azodicarbonamide still carries the volume in footwear despite the density gap.

Crosslinked polyolefin foam sheet#

Crosslinked polyolefin foam sheet is produced in two steps: the sheet is crosslinked first, by peroxide or by electron beam, and the azodicarbonamide is then decomposed so the strengthened melt can hold the gas. Sequence is everything, because a sheet that reaches the decomposition temperature before the network is built vents its gas and collapses.

In one study of radiation-crosslinked PP and POE foam, azodicarbonamide was used with the coagent TMPTMA at electron-beam doses of 2 to 20 kGy, crosslinking rose with TMPTMA content to about 8 phr and then plateaued, and the maximum reached 55 % at 15 kGy. The two-step route is set out on blowing agents for polyolefin foams.

Injection-molded structural foam and closure gaskets#

Injection-molded structural foam uses azodicarbonamide to take weight out of thick sections, and closure-sealing gaskets are the one US food-contact application with an explicit ceiling: 2 % of the gasket composition, or 5 % in polyethylene gaskets, under 21 CFR 177.1210. A small gas volume in a thick wall also holds pressure against the cavity while the part cools, which removes sink marks over ribs and bosses.

Weight reduction by chemical foaming sits beside the other additives for injection molding, at a reported 10 to 20 % less plastic, figures published by Avient as supplier claims. The gasket ceiling is a composition limit rather than a dosing recommendation.

How Does Azodicarbonamide Perform in a Foam?#

Azodicarbonamide delivers the highest gas yield of the common chemical blowing agents at 200 to 220 mL/g, against 120 to 125 mL/g for OBSH and 95 to 160 mL/g for bicarbonate grades, which is why it remains the volume standard for low-density foam. Only DPT, at 242 mL/g and a 205 °C (401 °F) decomposition point, beats it inside the chemical class, and DPT is a rubber-side agent.

Does more gas mean a lower density? Only if the melt holds it. In the EVA study behind the 1.35 phr formulation, chemical foaming reached 0.15 to 0.25 g/cm3 in a 170 to 190 °C (338 to 374 °F) window while physical foaming with nitrogen reached 0.13 g/cm3 in an 80 to 180 °C (176 to 356 °F) window, so the agent with twice the gas yield did not give the lower density. The limit was melt strength and process window.

The exotherm is the second performance term. Azodicarbonamide releases 1.36 kJ/g, while an endothermic bicarbonate system absorbs heat, gives finer cells and shortens the cooling step at a third to two thirds of the gas yield. A formulator therefore chooses azodicarbonamide when expansion ratio is the binding constraint, and a bicarbonate or microsphere route when cell fineness, cooling time or food-contact status binds instead.

Table T5. Azodicarbonamide performance against the alternatives.

No cell-size, tensile or compression-set value for an azodicarbonamide foam is held in our source library.

How Does Azodicarbonamide Interact with Kickers, Peroxides and Additives?#

Azodicarbonamide is formulated with 4 kinds of partner: activators that lower its onset, a second blowing agent that widens the window, a crosslinking peroxide that builds melt strength, and a coagent when the crosslinking is done by electron beam. The 4 partner classes are listed below.

• Activators, or kickers. Zinc oxide, zinc stearate and urea pull the onset from about 210 °C (410 °F) to 140 to 165 °C (284 to 329 °F).
• Co-blowing agents. OBSH blended with azodicarbonamide, as in the Eiwa Spangcell range, spreads the release across 150 to 185 °C (302 to 365 °F) at 150 to 180 mL/g.
• Crosslinking peroxides. BIPB at 0.5 to 0.7 phr and dicumyl peroxide build the network that holds the gas; the crosslinking partners are organic peroxides for polymers, chosen by half-life rather than by decomposition point.
• Coagents. TMPTMA raises the crosslinking yield of an electron-beam cure, with crosslinking rising up to about 8 phr in one study of PP and POE foam sheet.

Two of those partners carry their own regulatory identity. Zinc oxide is FCM substance 402 under Regulation (EU) No 10/2011, and dicumyl peroxide is the other crosslinker used beside azodicarbonamide in polyolefin foam, carrying its own Candidate List entry since 27 June 2024. No interaction between azodicarbonamide and a heat stabilizer, a light stabilizer or an antioxidant is recorded in our source library.

What Is the Regulatory Status of Azodicarbonamide under REACH, EU 10/2011 and 21 CFR?#

Azodicarbonamide is registered under REACH, has been on the Candidate List of substances of very high concern since 19 December 2012, is not in the EU food-contact Union list, has been suspended as a blowing agent in EU plastic food-contact materials since 2 August 2005, and is allowed in the United States at up to 5 % of the finished foamed polyethylene (status 24 September 2026). The matrix below sets each instrument against its dated status.

Table T6. Regulatory status of azodicarbonamide, as of 24 September 2026.

Registration, the Candidate List and the notification duties are explained under REACH and plastic additives, which separates a Candidate List entry from an authorisation requirement and from a restriction. Azodicarbonamide sits at the first stage and at neither of the other two.

Is azodicarbonamide an SVHC, and what must a supplier communicate (Article 33 and SCIP)?#

Yes: azodicarbonamide has been on the REACH Candidate List since 19 December 2012 because of its respiratory sensitising properties under Article 57(f), one of the 253 entries on the list as it stood after the 4 February 2026 update. Azodicarbonamide has been on the SVHC Candidate List since that date, which is the trigger date for every duty that follows.

Inclusion creates 3 duties once an article contains more than 0.1 % w/w of the substance.

• Article 33 communication. The supplier informs professional recipients of the article, and answers a consumer request within 45 days.
• Article 7(2) notification. A producer or importer notifies ECHA when the article exceeds 0.1 % w/w and 1 tonne per year per actor, within 6 months of inclusion.
• SCIP notification. The article is entered in the ECHA database of substances of concern in articles.

An article above 0.1 % w/w has to be entered in the SCIP database, a duty in force since 5 January 2021. Residual azodicarbonamide levels in a finished foam are not verified in our source library, so this page describes the duties without asserting that any foam crosses the threshold.

Is azodicarbonamide on REACH Annex XIV or Annex XVII?#

No: azodicarbonamide is not on the REACH Annex XIV Authorisation List and no Annex XVII entry restricts it, so Candidate List inclusion has not turned into an authorisation or a restriction (checked 22 September 2026). No entry of the REACH Annex XVII restrictions names azodicarbonamide, and the ECHA regulatory-process record for the substance shows the Candidate List and nothing beyond it.

Is azodicarbonamide allowed in food-contact plastics?#

No, not in the European Union: azodicarbonamide is absent from the Union list of Regulation (EU) No 10/2011, and its use as a blowing agent in plastic food-contact materials has been suspended since 2 August 2005 under Commission Directive 2004/1/EC, because it forms semicarbazide. The suspension is specific to that use in that material class, and it does not touch flooring, wall covering, footwear or technical foam.

Other blowing agents are listed, which gives a food-contact formulator a substitution path: carbonic acid salts as FCM 21, citric acid as FCM 139, carbon dioxide as FCM 307, n-pentane as FCM 244, isopentane as FCM 143, HFC-152a as FCM 131 and zinc oxide as FCM 402. The Union list of the plastic food contact materials regulation holds the endothermic and physical agents, but not azodicarbonamide. The United States keeps three positive listings instead, including up to 5 % of the finished foamed polyethylene under 21 CFR 178.3010.

What does the FDA allow, and what is the 2025 post-market assessment?#

The United States allows azodicarbonamide in three food-contact settings: up to 5 % of the finished foamed polyethylene under 21 CFR 178.3010, up to 2 % of a closure-sealing gasket composition (5 % in polyethylene gaskets) under 21 CFR 177.1210, and as a chemical blowing agent in rubber articles intended for repeated use under 21 CFR 177.2600. Sections 178.3010, 177.1210 and 177.2600 sit inside the FDA food contact rules for plastic additives (21 CFR), and each is a composition ceiling for the finished article rather than a recommended dose.

Two dated events stand on the public record. The Food and Drug Administration initiated a post-market assessment of ADA in food and food-contact uses on 19 August 2025 with a Request for Information under docket FDA-2026-N-4126, and a Federal Register notice titled "Azodicarbonamide (ADA); Request for Information" is dated 13 May 2026. The relationship between the two dates and the current stage of the assessment are not established, so both are stated as events and no outcome is inferred. An assessment that has been opened is not a ban.

Is Azodicarbonamide Safe to Handle? CLP Classification, Health and Safety#

Azodicarbonamide carries a harmonised EU classification as a respiratory sensitiser, category 1, with hazard statement H334, and that inhalation hazard is also the reason it sits on the REACH Candidate List. H334 reads "May cause allergy or asthma symptoms or breathing difficulties if inhaled", and it is the only harmonised classification the substance carries. The classification, the exposure route and the standard control are set out below.

• Classification. Harmonised Resp. Sens. 1, H334, under CLP Annex VI index 611-028-00-3. Notifiers to the ECHA classification and labelling inventory additionally report H228 as a flammable solid, H317 for skin sensitisation and H402 or H412 for aquatic hazard, which are notified rather than harmonised entries.
• Exposure route. Airborne powder during weighing, charging and compounding, not the finished foam, since the substance has decomposed by the time the part leaves the press.
• Control. Buying the substance as a masterbatch or a dust-free grade removes the airborne powder at the dosing station, a formulation practice rather than a regulatory exemption.

Index 611-028-00-3 is its entry in the CLP classification of plastic additives, and the same respiratory sensitising property supports both that entry and the Article 57(f) ground for Candidate List inclusion on 19 December 2012.

No occupational exposure limit, no LD50 and no NOAEL for azodicarbonamide is held in our source library, so this page states the classification and stops there. A handler works from the supplier safety data sheet and the H334 classification for the grade delivered.

What Are the Alternatives to Azodicarbonamide?#

The 6 alternatives to azodicarbonamide are OBSH and TSH for lower processing temperatures, sodium bicarbonate with citric acid for endothermic foaming, 5-phenyltetrazole for engineering plastics, expandable microspheres for closed-cell work under shear, and supercritical nitrogen or carbon dioxide for physical foaming. Each route trades gas yield for another property.

Table T7. Azodicarbonamide against the 6 alternative routes.

Values are representative supplier or literature figures, not specifications. No verified decomposition or gas-yield data for TSH or 5-phenyltetrazole is held in our source library.

Which route replaces which application is worked through on azodicarbonamide alternatives, where the substitution is driven by the binding constraint of each part rather than by the chemistry alone.

OBSH and TSH: the lower-temperature sulfonyl hydrazides#

OBSH decomposes at 160 to 165 °C (320 to 329 °F) and releases 120 to 125 mL of nitrogen and water vapour per gram, roughly half the gas of azodicarbonamide but with a milder exotherm and a residue that does not stain. OBSH decomposes about 45 °C lower than a standard azodicarbonamide grade, and PubChem records 150 to 160 °C (302 to 320 °F) with decomposition for the pure substance.

Blending is the third option. Eiwa Spangcell blends of azodicarbonamide and OBSH sit at 150 to 185 °C (302 to 365 °F) with 150 to 180 mL/g, which is how a formulator tunes the window without changing the chemistry twice. TSH blowing agent (p-toluenesulfonyl hydrazide), CAS 1576-35-8, is the second sulfonyl hydrazide, and no verified decomposition point or gas yield for it is held in our source library.

Sodium bicarbonate and citric acid: the endothermic route#

Sodium bicarbonate with a citric-acid activator is the endothermic alternative: it absorbs heat instead of releasing it, decomposes between 120 and 200 °C (248 and 392 °F) and gives 95 to 160 mL of carbon dioxide and water vapour per gram. Endothermic blowing agents absorb heat instead of releasing it, which changes the cell structure and the cooling time: two molecules of sodium bicarbonate give sodium carbonate, water and carbon dioxide, and the heat that reaction takes out of the melt produces finer cells.

Grade values sit inside that window, with Eiwa Cellborn grades at 150 °C (302 °F) and FE-512 at 196 °C (385 °F) and 190 mL/g. Sodium bicarbonate as a blowing agent is listed for EU food contact as carbonic acid salts, FCM 21, and citric acid is FCM 139, the only chemical route inside the Union list.

5-Phenyltetrazole: the high-temperature option#

5-Phenyltetrazole (CAS 18039-42-4) is the high-temperature option: it is used where an engineering thermoplastic such as polybutylene terephthalate is processed far above the azodicarbonamide window. Its EC number is 241-950-8, its formula C7H6N4 and its molecular weight 146.15 g/mol, and the PBT extrusion foaming application is reported by Jeong and co-workers in the review PMC7564929. Under REACH it is registered as an intermediate only, without a full Article 10 registration.

No decomposition point and no gas yield for 5-phenyltetrazole is held in our source library, so both come from the supplier technical data sheet.

Expandable microspheres and physical foaming with N2 or CO2#

Expandable microspheres and supercritical gas replace the chemistry entirely: the microsphere is a thermoplastic shell around a hydrocarbon core that expands between about 121 and 178 °C (250 and 352 °F), and microcellular molding dissolves supercritical nitrogen or carbon dioxide directly in the melt. Expandable microspheres keep their closed cells under shear, which is why they win in TPE and weather strip: Expancel 920 DU 40 starts at 121 to 131 °C (250 to 268 °F), peaks at 168 to 178 °C (334 to 352 °F) and expands to about 17 kg/m3. In one study, 1.5 wt% in HDPE injection molding gave a 5.75 % density reduction with cells around 90 µm.

Microcellular foaming (MuCell) removes the chemistry entirely and leaves no residue. It was invented in 1979 at MIT by J. E. Martini and F. A. Waldman under Nam P. Suh and trademarked by Trexel in 2001, and in one polycarbonate case study 2 % supercritical carbon dioxide gave a 17 to 32 % weight reduction.

Who Manufactures Azodicarbonamide? Grades and Suppliers#

Azodicarbonamide is made by a small number of specialist producers, the best documented being Eiwa Chemical, part of the Mitsubishi Gas Chemical group, which sells standard grades under the Vinyfor name, azodicarbonamide and OBSH blends as Spangcell and masterbatches as Panthlene. Dongjin Semichem, with the Unicell D-series, and Otsuka Chemical are reported as producers, but neither entry is verified against a primary source, so this page names them as reported and attaches no grade data to them.

Table T8. Azodicarbonamide producers, brands and grade families.

Celogen AZ and Genitron are legacy trade names whose current owner is not verified in our source library, so the names are listed without an owner.

Buyers should ask for the grade data sheet with the decomposition point and the gas volume, the safety data sheet, and a statement of the azodicarbonamide content of the delivered form, because masterbatch and activated grades are not interchangeable with neat powder. More producers are in the directory of blowing agent manufacturers and suppliers.

How Does Azodicarbonamide Fit into the Blowing Agent Family?#

Azodicarbonamide is the reference member of the chemical blowing agents, the group that also holds OBSH, TSH, TSSC, DPT and 5-phenyltetrazole, and it sits beside the physical agents and the expandable microspheres in the wider blowing agent family. DPT, at 205 °C (401 °F) and 242 mL/g, is the rubber-side member of the same class, and the sixth organic type in the Rostami-Tapeh-Esmaeil and Rodrigue review is the isocyanate and water system that generates carbon dioxide inside a polyurethane reaction.

Across the family, blowing agents account for 0.05 to 20 wt% of a finished foamed plastic. Where each chemistry sits in the blowing agent family is mapped on the family hub.

Azodicarbonamide trade names and their equivalents#

Azodicarbonamide is sold under at least 6 trade names, including Vinyfor, Spangcell and Panthlene from Eiwa Chemical, the Unicell D-series, the legacy names Celogen AZ and Genitron, and ADC 271 from Baerlocher. The abbreviations travel with the trade names, so ADC, ADCA and AC on a data sheet and ADA in a US regulatory document all resolve to CAS 123-77-3.

Cross-vendor equivalents are resolved with the plastic additive trade name lookup. The current owners of Celogen AZ and Genitron are not verified in our source library, so those two names appear here without an attributed company.

Non-plastics uses of azodicarbonamide: flour treatment and rubber sponge#

Outside plastics, azodicarbonamide has two uses that this reference does not cover: flour treatment, where 21 CFR 172.806 allows up to 45 ppm in flour and the European designation is E927, and expanded rubber, where 21 CFR 177.2600 lists it as a blowing agent for rubber articles. The flour use is a food-additive question governed by food law, and E927 is a flour-treatment designation rather than a plastics one. The rubber use belongs to the same chemical class treated here, with DPT as the blowing agent most associated with sponge rubber.

For the plastics question, which is what this page answers, the governing instruments remain Regulation (EU) No 10/2011 with Commission Directive 2004/1/EC, the REACH Candidate List and the three 21 CFR sections above.

Is azodicarbonamide banned in Europe?#

No. Its use as a blowing agent in plastic food-contact materials has been suspended in the EU since 2 August 2005 under Commission Directive 2004/1/EC, and it has been on the REACH Candidate List since 19 December 2012. It is not banned in plastics generally. No REACH Annex XVII entry restricts it in other plastics (checked 22 September 2026). The food-additive question, which is where the phrase comes from, is separate and is not treated on this site.

Does the bread story affect plastics compliance?#

No: a compounder's obligations for azodicarbonamide come from the REACH Candidate List entry of 19 December 2012 and from the 2005 food-contact suspension, not from the food-additive coverage. The one forward-looking item is dated and narrow: the FDA post-market assessment opened on 19 August 2025 covers food and food-contact uses, so buyers of foamed food-contact polyethylene track docket FDA-2026-N-4126 rather than the press cycle.

Azodicarbonamide price, trade data and documents#

No verified price series for azodicarbonamide is published on this page, because our source library holds no price figure from a dated, citable source. Where a dated price series exists, it is published under plastic additive prices. The comparison a buyer makes instead is on active content, because a 70 % masterbatch, an activated grade at 135 mL/g and a standard powder at 220 mL/g each buy a different gas volume per kilogram. HS codes and duty orders are collected under plastic additive trade.

Does azodicarbonamide need a safety data sheet?#

Yes: azodicarbonamide carries a harmonised classification as a respiratory sensitiser, so suppliers provide a safety data sheet, and a mixture containing 0.1 % or more must be accompanied by one on request even when the mixture itself is not classified. That second duty follows from the Candidate List entry rather than from the classification.