| HS Code | |
| Product Name | Acrylonitrile-Butadiene Copolymer |
| Abbreviation | NBR |
| Chemical Composition | Copolymer of acrylonitrile and butadiene |
| Acrylonitrile Content | 15–50% by weight |
| Appearance | Light yellow to amber rubbery solid |
| Density | 0.98–1.00 g/cm³ |
| Glass Transition Temperature | -40 to -20 °C |
| Mooney Viscosity Ml 1 4 At 100 C | 30–90 MU |
| Tensile Strength | 5–25 MPa |
| Elongation At Break | 100–600% |
| Hardness | 40–90 Shore A |
| Compression Set | 15–40% (70 h at 100 °C) |
| Service Temperature Range | -40 to 120 °C |
| Oil Resistance | Good to excellent |
| Fuel Resistance | Good |
| Ozone Resistance | Poor to moderate |
| Weather Resistance | Poor to moderate |
| Water Resistance | Good |
| Gas Permeability | Low |
| Flammability | Combustible |
| Dielectric Constant | 3–4 at 1 kHz |
| Volume Resistivity | 10^10–10^12 Ω·cm |
| Cure System | Sulfur or peroxide |
| Solubility | Soluble in ketones and aromatic hydrocarbons; resistant to aliphatic hydrocarbons |
As an accredited Acrylonitrile-Butadiene Copolymer factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Acrylonitrile-Butadiene Copolymer packaged in 25 kg sealed, polyethylene-lined fiber drums with proper hazard labels and handling instructions. |
| Container Loading (20′ FCL) | Acrylonitrile-Butadiene Copolymer loaded in a 20′ FCL shipping container, securely palletized, sealed, marked, and properly documented for safe ocean transport. |
| Shipping | Acrylonitrile-Butadiene Copolymer is generally shipped as a non-hazardous solid in sealed bags, drums, or bales. Use UN-approved packaging where applicable. Keep containers closed, dry, cool, and well-ventilated, away from ignition sources and oxidizers. Follow local, national, and international transport regulations; latex or residual-monomer grades may need special handling. |
| Storage | Store acrylonitrile-butadiene copolymer in a cool, dry, well-ventilated area away from direct sunlight, heat, sparks, and open flames. Keep containers tightly closed and protect from moisture, ozone, and strong oxidizers. Maintain moderate temperature, avoid excessive stacking, rotate stock, use secondary containment, and follow manufacturer instructions and local regulations. |
| Shelf Life | Typically 2–5 years in sealed containers when stored cool, dry, away from direct sunlight, heat, and ozone. |
Inside automotive fuel-hose extrusion lines running 30–45 m/min with inner-tube wall thickness 1.5–2.5 mm, acrylonitrile-butadiene copolymer selected at 33% bound ACN and Mooney viscosity ML(1+4)100 °C of 50–60 is blended with 65–75 phr N550 carbon black, 15–20 phr trioctyl trimellitate, 5.0 phr zinc oxide, 1.0 phr stearic acid, 1.5 phr polymerized 2,2,4-trimethyl-1,2-dihydroquinoline, 1.5 phr sulfur, 1.2 phr N-cyclohexyl-2-benzothiazolesulfenamide, and 0.5 phr tetramethylthiuram disulfide in a 60 L intermeshing internal mixer with ram pressure 0.6 MPa and discharge at 125–135 °C. The batch is sheeted on a two-roll mill with 0.5 mm nip gap and extruded through a 120 mm cold-feed extruder with L/D 20:1 and barrel temperature profile 65–75 °C from feed zone to head. Carbon-black moisture above 0.5 wt% causes steam porosity in the extruded inner tube because the compound contains no desiccant additive; conveying air for carbon-black storage is dried to a dew point below −40 °C. Batch-to-batch Mooney viscosity variation of ±3 MU shifts extruder head pressure by 8–10% on the 120 mm cold-feed extruder, requiring screw speed correction of 1.5–2.0 rpm to hold inner-tube diameter within ±0.2 mm. The cooled inner tube is reinforced with 1,100 dtex aramid or polyester braid under 80–120 N tension and covered with a second NBR compound containing 2.0 phr wax and 3.0 phr N550. Vulcanization proceeds in a saturated-steam autoclave at 0.45–0.55 MPa gauge pressure for 60–90 min; the cured hose is verified by ASTM D471 for volume swell below 30% after 70 h at 100 °C in IRM 903 and by ASTM D1053 for T10 below −25 °C. Final products are SAE J30 R7 fuel feed hoses, SAE J30 R8 vapor return lines, and low-pressure fuel injection return hoses. EU-facing shipments are screened against REACH 1907/2006 Annex XVII restricted substances and OEM evaporative emission plasticizer migration limits.
At the bulkhead of a high-pressure wireline retrievable production packer, the sealing element compound must withstand simultaneous exposure to 15–20% H₂S in methane, thermal cycling from −20 °C to 120 °C, and rapid gas decompression after pressure drops from 10,000 psi to atmospheric. A starting formulation for compression-moulded elements uses 100 phr NBR with 41% ACN and Mooney viscosity ML(1+4)100 °C of 75–85, 55–65 phr N330 carbon black, 10–15 phr N774 carbon black, 5.0 phr zinc oxide, 1.0 phr stearic acid, 1.5 phr TMQ, 1.5 phr sulfur, 1.0 phr dibenzothiazyl disulfide, and 0.8 phr TMTD. The compound is mixed in a 45 L internal mixer with an initial fill factor of 0.75 and discharged at 120–130 °C, then calendered to 8–10 mm preforms. Moulding is performed in a 1,000 t compression press at 170 °C with 18–20 MPa flash pressure on a multi-cavity packer element tool, followed by forced-air post-cure at 150 °C for 4 h. Qualification follows ISO 23936-2:2011 and NORSOK M-710 Edition 3, with sour-liquid exposure conducted under NACE TM0297; published data for specific H₂S-CO₂ mixed gas permeation under high differential pressure remain limited relative to total volume swell data, so sealing-component validation typically adds rapid gas decompression testing according to the annex of ISO 23936-2:2011. Terminal products are production packer elements, blowout preventer ram rubbers, and subsurface safety valve seals; low-temperature variants substitute 28% ACN NBR at the expense of higher IRM 903 swell.
| Bound ACN content | IRM 903 volume swell after 70 h at 100 °C | Gehman T10 by ASTM D1053 | Typical seal application |
|---|---|---|---|
| 28% | 35–45% | −30 °C | Low-temperature packer backup seals |
| 33% | 25–30% | −25 °C | General hydraulic rod seals |
| 41% | 8–14% | −15 °C | Sour-gas packer elements |
| 45% | 5–10% | −10 °C | High-aromatic fuel and oil seals |
Values are typical ranges compiled from NBR producer technical datasheets and are not specification limits.
When residual calcium nitrate in the coagulant dip exceeds 20% w/v, carboxylated NBR films develop pinholes at the former tip due to rapid surface skinning, and the resulting gloves fail the AQL 1.5 barrier criterion under ASTM D6319. A production-grade carboxylated NBR latex compound is prepared at 100 phr dry rubber with 1.0–1.2 phr sulfur, 0.8 phr zinc oxide, 0.8–1.2 phr zinc diethyldithiocarbamate, 0.5 phr titanium dioxide, 0.3 phr potassium hydroxide, and 0.1 phr silicone defoamer; the matured latex is maintained at 28–32 °C and 2,500–3,000 cP viscosity during dipping. Ceramic formers are washed with 0.5% sodium hydroxide at 60 °C, dipped in 15–20% calcium nitrate coagulant for 10–20 s, dried at 60–70 °C, then immersed in the compounded latex for 60–120 s. The wet gel is pre-cured at 80–90 °C for 3–5 min, leached in hot water at 50–65 °C for 30–60 s to remove water-soluble accelerators, and main-cured in forced-air ovens at 120–140 °C for 20–25 min. Final products are nitrile examination gloves and cleanroom gloves; compliance is confirmed by ASTM D6319, EN 455-1, EN 455-2, EN 455-3, EN 455-4, ISO 374-1:2016, and FDA 21 CFR 177.2600 for repeated-use food-handling classifications where applicable.
For a steel mill bridle roll cover, a calendered NBR compound of 100 phr NBR with 33% ACN and Mooney viscosity ML(1+4)100 °C of 60 uses 55 phr N550, 15 phr dioctyl phthalate, 7.0 phr zinc oxide, 1.0 phr stearic acid, 1.5 phr sulfur, and 1.2 phr CBS. The compound is mixed in a 35 L internal mixer and sheeted on a calender to 3–5 mm thickness. The steel core is degreased, grit-blasted to Sa 2.5, primed with a solvent-borne rubber-to-metal adhesive, and wrapped with the calendered sheet at 45° bias angle; subsequent layers are rotated 90° to reduce grain-direction shrinkage. The roll is spiral-wrapped with nylon tape at 1.2–1.5 mm overlap and 1.0 kN/m linear tension before autoclave vulcanization at 142–148 °C for 90–120 min. After cure, residual shrinkage above 0.5% consumes the grinding allowance and produces vibration under line speeds above 300 m/min; rolls are conditioned at 23 °C and 50% RH for 48 h before cylindrical grinding to runout ≤0.025 mm. Compliance is verified by ISO 6123-1:2015 for rubber-covered rollers, hardness by ASTM D2240 durometer, and surface roughness by ISO 4287. Terminal products include nip rolls, bridle rolls, and printing press distribution rollers.
In a single-station injection moulding machine with an 18:1 L/D screw and 80–100 MPa injection pressure, a heat-sensitive NBR/PVC soling compound is processed at 175–185 °C to avoid PVC dehydrochlorination above 190 °C and NBR scorch above 125 °C Mooney t5. The compound consists of 100 phr NBR with 28–33% ACN, 20–30 phr suspension PVC, 5.0 phr zinc oxide, 1.0 phr stearic acid, 1.5 phr sulfur, 1.0 phr MBTS, 0.3 phr TMTD, 40–60 phr precipitated silica, 5–10 phr naphthenic oil, and 2.0 phr coupling agent. The dry blend is discharged from a high-speed mixer at 110–120 °C, cooled to 40 °C, and fed as pellets with melt temperature monitored at the nozzle; cycle time is 60–90 s for 10 mm sole thickness. Finished outsoles are tested for oil resistance by ASTM D471 after 70 h at 23 °C in IRM 903 and for abrasion by DIN 53516 with a target volume loss below 150 mm³. Compliance is linked to EN ISO 20345:2022 for safety footwear, and terminal products are S1 and S2 rated oil-resistant outsoles for food-processing and petrochemical plant footwear.
Dissolved in a 70:30 methyl ethyl ketone/toluene blend at 18–22% solids, NBR with 33% ACN and Mooney viscosity ML(1+4)100 °C of 40 is used as the flexibilizing binder in aromatic-solvent-resistant rubber-to-metal bonding systems for underhood brackets. The dry compound is prepared on a two-roll mill at 60–70 °C using 100 phr NBR, 40–60 phr resole phenolic resin, 5.0 phr zinc oxide, 1.0 phr stearic acid, 1.5 phr TMQ, 0.5 phr sulfur, and 0.3 phr TMTD; the milled sheet is then granulated and dissolved in a high-speed disperser at 1,200 rpm for 4–6 h, followed by filtration through a 50 µm mesh. The adhesive is applied by air-atomized spray to phosphated steel substrates at 8–12 µm dry film thickness, air-dried for 15–20 min, and then over-moulded with NBR in a 300 t injection press at 160–180 °C. Solvent handling is conducted within facilities following REACH 1907/2006 volatile organic solvent emission limits; adhesion strength is determined by ASTM D429 Method B and must exceed 6.0 kN/m peel strength before rubber tear. Terminal products are metal inserts for engine mounts, control-arm bushings, and torque-rod bushings.
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Acrylonitrile-butadiene copolymer, designated NBR by ASTM D1418 and ISO 1629, is an emulsion-polymerized synthetic elastomer produced from acrylonitrile and butadiene. Commercial supply forms include bale, crumb, and powder; trade designations typically encode nominal bound acrylonitrile content and Mooney viscosity. Published technical data sheets list bound acrylonitrile contents between 18 wt% and 50 wt%, with Mooney viscosity ML(1+4) at 100 °C ranging from 30 MU to 90 MU. Specific gravity values fall between 0.96 and 1.02 across the commercial range. The product's value derives from a tunable balance: bound acrylonitrile raises cohesive energy density and aliphatic hydrocarbon resistance, but raises glass transition temperature and reduces low-temperature flexibility. This trade-off governs grade selection in sealing, fuel-handling, and industrial rubber goods.
Producers do not operate a unified model-number system. In common practice, a grade described as NBR 33 or NBR 33xx indicates nominal bound acrylonitrile near 33 wt%, with suffix digits or letters assigned to ML(1+4) viscosity, emulsifier type, or stabilizer package. Because published data for specific numeric suffixes is limited, end users should treat producer technical datasheets as the controlling specification rather than inferring properties from the trade designation alone. Bound acrylonitrile is the primary specification parameter; free acrylonitrile monomer concentration is controlled separately and is typically below 10 ppm in modern grades designed for skin-contact or potable-water adjacent applications. The polymer is random in monomer sequence, but emulsion polymerization can yield compositional drift at high conversion, so tight control of conversion is exercised when uniform oil resistance is required.
| Nominal bound ACN content | Indicative glass transition range | Indicative low-temperature flex range | Specific gravity | Relative aliphatic oil resistance |
|---|---|---|---|---|
| 18 wt% | -50 °C to -45 °C | -40 °C | 0.96–0.98 | Low |
| 28 wt% | -40 °C to -35 °C | -35 °C | 0.98–1.00 | Moderate |
| 33 wt% | -30 °C to -25 °C | -30 °C | 0.98–1.00 | High |
| 41 wt% | -20 °C to -15 °C | -20 °C | 1.00–1.02 | Very high |
| 50 wt% | -10 °C to -5 °C | -10 °C | 1.00–1.02 | Very high |
Beyond ACN content, Mooney viscosity and gel content influence processability. Low-viscosity grades flow readily in injection molding but may exhibit lower green strength; high-viscosity grades improve extrusion dimensional stability but require higher torque. Gel content above producer specification can create undispersed microgel domains that reduce tensile and fatigue life in dynamic applications. A typical general-purpose NBR 33 compound may exhibit hardness of 70 Shore A, tensile strength of 15 MPa, elongation at break of 350%, and compression set of 25% after 22 h at 100 °C under ASTM D395 Method B. These values shift with filler type, plasticizer loading, and cure system.
Specification conformance is established through a matrix of standardized test methods rather than a single material standard. The table below consolidates the principal test methods cited in NBR procurement specifications.
| Property | ASTM method | ISO method | Typical industrial range |
|---|---|---|---|
| Classification/designation | ASTM D1418 | ISO 1629 | NBR |
| Mooney viscosity | ASTM D1646 | ISO 289-1 | 30–90 MU |
| Hardness | ASTM D2240 | ISO 48 | 40–95 Shore A |
| Density | ASTM D792 | ISO 1183 | 0.96–1.02 g/cm³ |
| Tensile stress-strain | ASTM D412 | ISO 37 | 10–25 MPa tensile strength; 300–700% elongation |
| Compression set | ASTM D395 | ISO 815 | 15–45% after 22 h at 100 °C |
| Fluid resistance | ASTM D471 | ISO 1817 | Volume change depends on fluid and ACN content |
| Tear strength | ASTM D624 | ISO 34-1 | 20–50 kN/m |
Compliance statements for a given formulation are relevant only when the complete compound recipe is fixed, because additives such as plasticizers, fillers, curatives, and antidegradants shift final properties. Formulations intended for repeated food-contact use can be designed to meet FDA 21 CFR 177.2600, but the base polymer alone does not confer regulatory approval. REACH and RoHS documentation is supplier-specific and depends on residual monomer, catalyst residues, and processing aids.
Vulcanization behavior is formulation-dependent and is typically characterized using a moving-die rheometer according to ISO 6502 or ASTM D5289. Typical cure traces for sulfur-cured NBR compounds at 170 °C show minimum torque ML between 1.5 dN·m and 4.0 dN·m and maximum torque MH between 8 dN·m and 20 dN·m, depending on filler loading. The t90 value for fast-cycling injection molding grades is often compressed to 2–5 min, while compression molding grades may use t90 of 8–15 min. Thick-section parts require lower curing temperatures to avoid reversion and porosity.
Heat aging is evaluated by ASTM D573 or ISO 188. Typical acceptance criteria for NBR sealing compounds are less than 15 points Shore A hardness change and not more than 50% loss of tensile after 70 h at 100 °C. Ozone resistance is evaluated by ASTM D1149 or ISO 1431-1; straight NBR without antiozonant shows cracking within 24 h at 50 pphm ozone, which is a critical limitation for outdoor seals.
Low-temperature performance is not defined by a single number. Gehman torsional stiffness, TR-10 retraction, and brittleness point data are generated under ASTM D1053, ASTM D1329, and ASTM D2137 respectively. A compound may have a TR-10 of -25 °C yet still seal statically at lower temperatures if compression set is acceptable. Dynamic seals require comparison of the minimum service temperature with the glass transition onset measured by differential scanning calorimetry at 10 K/min.
Compound design starts from the end-use fluid and temperature envelope. For continuous mineral oil exposure below 100 °C, a 33 wt% ACN grade with 70 Shore A hardness is a frequent starting point. For ASTM Reference Fuel A or B exposure, users often raise ACN to 41 wt% or 50 wt% and reduce plasticizer content, accepting a loss of low-temperature flexibility. Sulfur-cured systems provide good tear and fatigue resistance; peroxide-cured systems provide improved compression set and heat aging at the cost of lower hot-tear strength and more critical processing control.
Fillers modify property profiles. Carbon black grades N550 and N774 are used in sealing compounds; N330 increases tensile and abrasion resistance but raises compound viscosity. Precipitated silica in rolling-element seal compounds improves tear strength and reduces heat build-up, but requires silane coupling agents. Mineral fillers such as calcium carbonate reduce cost and oil swell but can degrade compression set and water resistance. Plasticizer selection is equally critical: ester plasticizers improve low-temperature flexibility but are extractable in polar fluids, so high-temperature petroleum service compounds use lower-volatility polymerics or high-ACN grades.
High-ACN grades increase polarity, viscosity, and dissipative heating during mixing. On a production-scale internal mixer, batches based on 41 wt% or 50 wt% ACN grades commonly require rotor speed reductions of 10–20% relative to 28 wt% ACN grades to keep discharge temperatures below 120 °C. In two-roll mill operations, the friction ratio is maintained between 1.15:1 and 1.25:1, and roll temperatures are held below 50 °C for sulfur-containing compounds to avoid scorch. Intermeshing twin-screw extruders with L/D 32:1 to L/D 44:1 are used for continuous mixing, with barrel set points between 70 °C and 110 °C and screw speeds derated when bound ACN exceeds 41 wt%.
Mooney scorch values at 125 °C for high-ACN sulfur-donor compounds may show t5 below 8 min, so two-stage mixing or split-curative addition is common. In injection molding, machines with clamp force capacities of 1,000 kN to 5,000 kN are used for multicavity NBR seal production; cavity pressures between 40 MPa and 80 MPa are typical, with mold temperatures from 160 °C to 190 °C. High-ACN grades require pre-drying at 60–70 °C for 2–4 h when storage RH exceeds 60% or when molded parts show surface porosity. Continuous exposure to ketones, esters, chlorinated solvents, and strongly polar aromatic fluids is outside the product's chemical compatibility envelope; swelling and extraction can exceed 50% volume change under ASTM D471 immersion. Avoid substitution of amine-containing antidegradants without revalidating Mooney scorch, because cure acceleration may occur.
NBR compounds are used in hydraulic and pneumatic seals, O-rings, gaskets, hose covers, oil-well packer elements, roll covers, shoe soles, and cable jackets. In mineral-oil hydraulic service, NBR is the default elastomer for O-rings specified to ISO 3601-1, provided the continuous fluid temperature remains below 100 °C. For automotive fuel systems, NBR appears in hose covers and vapor-management components; it is not a primary permeation barrier for low-emission fuel systems, where fluoropolymer inner liners are used. Published field data from injection-molded seal production indicate that cavity-to-cavity dimension stability is closely tied to consistent Mooney viscosity; a shift of 5 MU can alter flash thickness and part weight beyond 1.5% in multicavity tools.
Low-ACN grades near 18 wt% are selected for low-temperature rotary seals and aircraft hydraulic applications where brittleness at -40 °C is a qualification criterion. The trade-off is increased swell in aliphatic oils and fuels; users must verify volume change and extraction limits against the specific fluid using ISO 1817 or ASTM D471. Grades with 33 wt% ACN are the most common general-purpose sealing choice because they balance oil resistance and low-temperature flexibility for industrial O-rings. In adhesives and sealants, nitrile copolymers are used as binders because they combine hydrocarbon resistance with compatibility with phenolic and epoxy curing resins.
Production-scale failure modes include porosity in thick sections, scorch during long extruder dwell times, and batch-to-batch viscosity drift from raw polymer variation. When Mooney viscosity shifts by more than 5 MU, injection molding machines require shot size and back pressure adjustments; otherwise flash increases and cavity fill becomes inconsistent. Mixing torque curves are monitored on internal mixers; an upward drift in final torque at constant rotor speed indicates increased gel or higher filler incorporation and is used to reject batches before molding.
Chemical incompatibility boundaries are sharp. High ACN does not make NBR resistant to aromatic hydrocarbons: benzene, toluene, and xylene swell NBR severely. Ketones and esters can produce high equilibrium swell. Chlorinated solvents extract plasticizer and cause severe swelling. Low-molecular-weight gasoline blends with high aromatic content are more aggressive than aliphatic fuels. In biodiesel blends, fatty acid methyl esters may extract plasticizers and create volume change; users should test according to ASTM D471 with the actual fuel blend rather than reference fluids alone.
Unvulcanized NBR compounds have limited shelf life. Sulfur-cured compounds stored above 30 °C may scorch and lose accelerator activity. Typical controlled storage is 15–25 °C with 50% maximum relative humidity; producer datasheets usually assign a shelf life of 6–12 months for mixed compounds, but final cure behavior must be verified before production release.
Polychloroprene (CR) is often selected for weathering and flame resistance, but its aliphatic hydrocarbon resistance is lower than that of medium- and high-ACN NBR. Under ASTM D471 immersion in IRM 901 oil at 100 °C for 70 h, a 33 wt% ACN NBR compound typically exhibits lower volume swell than a CR reference compound of equivalent hardness. The penalty is ozone resistance: unprotected NBR will crack under ozone exposure that is routinely survived by CR, so antiozonants or NBR/PVC blending are required for outdoor service. Low-temperature properties also diverge; CR retains flexibility below -30 °C in some grades, while high-ACN NBR becomes leathery above -20 °C.
Against EPDM, the distinction is more severe: EPDM has superior ozone, heat, and steam resistance, but swells heavily in mineral oil and hydrocarbon fuels, whereas NBR is specified for aliphatic fluid contact. Against SBR, NBR offers substantially better oil and fuel resistance at the expense of higher cost and reduced low-temperature flexibility. Against HNBR, the hydrogenated polymer provides service temperature extension to 150 °C and better oxidative stability, but at higher cost and with higher processing viscosity. Against FKM, NBR cannot match long-term sealing performance above 150 °C or in aggressive solvents, acids, and biodiesel blends, but NBR remains selected where cost and hydrocarbon resistance are sufficient.
NBR/PVC polyblends at 70/30 or 60/40 ratios are used for cable jackets, hose covers, and shoe soles where ozone resistance and melt processing are improved relative to straight NBR. Compression set data according to ASTM D395 Method B after 22 h at 70 °C generally increase as PVC content rises; values above 55% are common for plasticized 40 wt% PVC blends, limiting their use in dynamic seals where recovery is critical. The blend also raises the low-temperature stiffening point, making it unsuitable for -30 °C flex requirements. Sulfur, peroxide, and mixed cure systems are used, but the PVC phase reduces the efficiency of radical cure systems because hydrogen abstraction and dehydrochlorination compete with crosslinking at processing temperatures above 160 °C.
