Nitrile Rubber CAS 9003-18-3

What is Nitrile Rubber?

Nitrile rubber is a copolymer of butadiene and acrylonitrile, and the acrylonitrile content is what gives it the oil resistance that defines its market.

Bound ACN typically runs from 18 to 50%. Higher ACN gives better oil and fuel resistance but worse low-temperature flexibility, and that trade-off is the central decision in every NBR specification.

Dry NBR goes into seals, O-rings, gaskets, hose and roll covers; NBR latex goes into examination and industrial gloves, where it has largely displaced natural rubber latex because it carries no protein allergens.

NBR has poor ozone and weather resistance because of its unsaturated backbone, which is why outdoor applications use hydrogenated NBR or a different elastomer entirely.

Why nitrile rubber specifically

• Oil and fuel resistance. The polar nitrile groups resist swelling by hydrocarbons, which diene rubbers cannot do.
• Tunable by ACN content. The oil resistance versus cold flexibility balance is set by one composition variable.
• No protein allergens in latex. NBR gloves have replaced natural rubber latex in healthcare for exactly this reason.
• Cost-effective sealing. Far cheaper than fluoroelastomers for the great majority of oil-contact duties.

How Nitrile Rubber is Manufactured

Nitrile rubber is made by emulsion copolymerisation of butadiene and acrylonitrile, hot or cold.

• Monomer feed. Inhibited butadiene and acrylonitrile in the ratio that sets bound ACN content.
• Emulsion polymerisation. Carried out in soap solution with a redox initiator, cold at about 5 °C or hot at 30 to 40 °C.
• Conversion control. Polymerisation is stopped short of full conversion to control gel and branching.
• Monomer recovery. Unreacted butadiene and acrylonitrile are stripped and recycled.
• Latex finishing. Latex grades are concentrated and stabilised for glove dipping.
• Coagulation and baling. Dry grades are coagulated, washed, dried and baled at 25 to 35 kg.

Typical Commercial Specification

Figures below are representative of a medium-ACN dry nitrile rubber. Latex and specialty grades differ — tell us the application and we will send the matching sheet.

Physical & Chemical Properties

Behaviour in the process

NBR performance is a single trade-off expressed in several ways:

• ACN raises oil resistance, lowers cold flexibility. The core design decision; every other property follows from where you set it.
• Poor ozone resistance. The unsaturated backbone is attacked by ozone; outdoor seals need protection or HNBR.
• Swells in polar solvents. Resistant to hydrocarbons but attacked by ketones, esters and chlorinated solvents.
• Low gas permeability. High-ACN grades are good gas barriers, useful in refrigeration and fuel systems.

NBR Grades and Alternative Elastomers

Nitrile rubber is bought by bound ACN content and Mooney viscosity, with specialty variants for demanding duties.

Stated plainly: choosing ACN content is the whole specification. Default to 33% only when the duty is unremarkable; if the seal sees cold or sees fuel, the grade should be chosen deliberately.

Industries We Supply Nitrile Rubber To

NBR serves automotive, oil and gas, healthcare and industrial markets.

Where Nitrile Rubber is Used

Seals, gaskets and hose take the largest dry NBR volume, while glove manufacture dominates NBR latex.

Choosing ACN content

At 18 to 28% bound ACN the rubber stays flexible to about −45 °C but swells appreciably in fuel; at 45 to 50% it resists fuel almost completely but stiffens by 0 °C. Most general purpose seals sit at 33%. Where a component must do both — cold start and fuel contact — the usual answer is a mid-ACN grade with a plasticiser package rather than an extreme grade.

NBR latex gloves

Carboxylated NBR latex has largely replaced natural rubber latex in medical gloves because it carries no protein allergens and gives better puncture and chemical resistance. Latex grades are specified on total solids, viscosity, pH and particle size rather than on Mooney viscosity, and the dipping process is sensitive to all of them.

Quality Control & Testing

Every lot is released against a batch-specific Certificate of Analysis with the grade's defining properties, so your compound laboratory can release against the actual material.

• Mooney viscosity — ML (1+4) at 100 °C, the primary processing indicator.
• Bound acrylonitrile content — the defining composition figure for oil resistance.
• Volatile matter and ash — confirming drying and residue levels.
• Soap and organic acid content — emulsion residues that affect cure behaviour.
• Antioxidant type — staining or non-staining, relevant for light-coloured goods.
• Latex properties — total solids, pH, viscosity and particle size for dipping grades.

Common Process Problems & Likely Causes

When NBR causes trouble, it is usually ACN mismatch, cure variation or ozone attack. This table is the shortcut our technical desk works through before anyone opens a complaint file.

Packaging, Storage & Shipping

• Standard packing. 25 to 35 kg bales in polyethylene film for dry grades; drums and IBCs for latex.
• Storage. Cool, dry, covered warehousing below 30 °C, away from direct sunlight.
• Ozone protection. Keep away from electrical equipment generating ozone; NBR is particularly vulnerable.
• Latex handling. Keep latex above freezing and below 30 °C; agitate periodically and avoid contamination.
• Segregation. Keep ACN grades clearly separated; bales are visually similar.
• Stack height. Limit stacking to prevent bale deformation in warm conditions.
• Shelf life. Dry grades typically 12 to 24 months; latex typically six months with periodic agitation.
• Transport classification. Not classified as dangerous goods for transport.

Hazards & Safe Handling

NBR is an inert polymer with no significant health hazard in normal handling. The practical concerns are manual handling of bales, mixing fume and, for latex, the accelerator package in finished gloves.

• Inert in normal handling. Not classified as hazardous. Bales present no chemical risk in storage or transport.
• Manual handling. Bales are a significant ergonomic hazard; use mechanical handling where possible.
• Mixing fume. Internal mixer and mill operations generate rubber process fume; ventilation and extraction are required.
• Accelerator sensitisation. Thiuram and carbamate accelerators in glove compounds cause Type IV allergy in some users; accelerator-free formulations exist.
• Compound ingredients. Curatives, plasticisers and fillers carry their own hazards; the compound SDS governs.
• Environment. Inert but persistent; contain waste and use established rubber recycling routes.

Regulatory & Compliance Notes

NBR is unregulated for transport, with medical device and food contact rules applying downstream. The notes below are orientation rather than legal advice.

• GHS classification. Not classified as hazardous.
• Transport. Not classified as dangerous goods. Standard packaged cargo documentation applies.
• Medical gloves. Examination and surgical gloves are regulated medical devices under EU MDR, FDA and equivalent regimes, with ASTM and EN standards applying.
• Food contact. NBR goods for food contact require compliance documentation at compound level.
• Residual monomer. Residual acrylonitrile is controlled, with tighter limits for medical and food contact applications.
• REACH and inventories. Polymers are exempt from REACH registration, though monomers and additives are not.

We Supply Nitrile Rubber Worldwide

Chelora Chemicals is a supplier and export partner, not a single-plant trader. We ship Nitrile Rubber from India and from partner sources to customers across Asia, Europe, the Middle East, Africa, and North and South America, handling the export documentation, transport paperwork and freight so the material arrives ready to use.

• Incoterms. EXW, FOB, CIF, CFR and DAP quoted to suit your purchasing terms and freight arrangements.
• Ports. Regular shipments through Nhava Sheva (JNPT) and Mundra, with other ports arranged where routing and cargo rules allow.
• Documentation. Commercial invoice, packing list, certificate of origin, COA, SDS and the transport declaration issued as a complete set.
• Flexible volumes. From a pallet of bales up to repeat bulk shipments on a supply contract.
• Supply continuity. Because we are independent of any one producer, a plant turnaround or a shipping disruption at one source does not have to become your stock-out.

Buying Nitrile Rubber from Chelora

We are an independent sourcing and supply partner. For nitrile rubber that means settling three things at enquiry: the bound ACN content your fluid and temperature duty requires, dry or latex supply, and whether medical or food contact documentation applies.

• Documentation on every lot. Batch-specific COA (Mooney viscosity, bound ACN, volatiles, ash), plus SDS and the full transport paperwork.
• Analysis before commitment. Representative analysis shared ahead of a commercial order so your lab can qualify the material.
• Quantities. From a pallet of bales through to full bulk shipments on contract supply.
• Grade matching. Low, medium or high ACN nitrile rubber, dry or latex, at the Mooney viscosity your process requires.
• Inspection. Independent third-party inspection available at loading when the contract requires it.
• Related products. Acrylonitrile, 1,3-Butadiene, Styrene-Butadiene Rubber and other feedstocks alongside Nitrile Rubber from one supplier.

How ordering works

• Send the enquiry. Product, grade or purity, quantity, destination port and the Incoterm you buy on. If you have a spec sheet, attach it — it saves a round trip.
• We quote. Price, lead time, packing format and a sample COA, normally within one working day.
• Qualify the supply. For first orders or critical applications, we share the analysis and handling documentation so your technical and safety teams can sign off before you commit.
• Confirm the order. Proforma invoice issued; payment terms agreed against the volume and the relationship.
• Allocation and QC. Material allocated and released against a batch-specific COA, with an independent inspection where the contract calls for it.
• Ship and document. Filled, labelled and loaded with the full export document set, and tracked through to arrival.

Related Products

Buyers of nitrile rubber often source related elastomers and monomers alongside it — butadiene, acrylonitrile and other rubbers are commonly bought on the same programme.