NBR

Core Equipment

Polymerization KettlePressure-resistant stainless steel reactor with jacket and internal coil cooling, high-intensity agitation, and liquid ammonia cryogenic refrigeration. Pre-emulsifier / High-speed EmulsifierFully emulsifies the oil and aqueous phases to ensure uniform reaction and stable molecular weight. Degassing Tower & Flash TankRemove unreacted butadiene and acrylonitrile to reduce residual monomer content. Coagulation KettleDemulsifies latex by adding salt to form rubber crumbs. Extrusion Dehydrator & Expansion DryerRealize continuous dehydration and drying, ensuring moisture content < 1%. Baling Press & Automatic Packaging LineProduce standard rubber bales suitable for export by sea and rail transportation.

Reaction carried out at 5–15°C, delivering uniform molecular structure and excellent physical properties. Redox Initiation TechnologyInitiates efficiently at low temperatures with stable reaction, minimizing branching and cross-linking. Mooney Viscosity Control TechnologyUses mercaptan regulators to control processing fluidity. Continuous Post-Treatment TechnologyIntegrated coagulation–dehydration–drying process ensures export-grade appearance and consistent quality.

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产品介绍

Medium-High Nitrile Butadiene Rubber (Medium-High NBR) is a general-purpose synthetic rubber with excellent oil resistance, widely used in industrial sealing and automotive fields. It is a copolymer synthesized from acrylonitrile (AN) and butadiene monomers through emulsion polymerization. The acrylonitrile content is in the medium-high range, which gives it an outstanding balance between oil resistance, elasticity and processability.

Physically, medium-high nitrile NBR is a light yellow elastic solid with excellent oil resistance, fuel resistance and organic solvent resistance. It also has good tensile strength, abrasion resistance and aging resistance. Compared with low-nitrile NBR, it has stronger oil and chemical resistance; compared with high-nitrile NBR, it has better elasticity, low-temperature performance and processing performance, making it widely adaptable.

The production of medium-high nitrile NBR mainly adopts emulsion polymerization, with stable and mature technology. By adjusting the acrylonitrile content, polymerization process and molecular structure, products with different performance indicators can be produced to meet the requirements of various working conditions.

Medium-high nitrile NBR is mainly used in oil-resistant rubber products, such as oil seals, O-rings, gaskets, hoses, diaphragms and rubber rollers. It is widely used in automotive engines, transmission systems, fuel systems, hydraulic equipment and mechanical sealing parts. It is also used in petroleum, mining, electrical appliances and other industrial fields that require both oil resistance and elasticity.

Overall, medium-high nitrile NBR is a high-performance rubber material with excellent oil resistance, mechanical properties and processability. It is an irreplaceable key material in many industrial applications requiring oil resistance and durability.

Types and Characteristics of Equipment

Type

Medium High Acrylonitrile Nitrile Butadiene Rubber (NBR): Refers to nitrile butadiene rubber with a combined acrylonitrile content ranging from 31% to 35%. It is currently the most mainstream and highest-demand grade for export to markets including Russia, the Middle East, Tanzania, etc.It is mainly used in oil-resistant seals, hoses, rubber belts, oilfield products, automotive parts, rubber components for engineering machinery, and other applications.

Features

Excellent oil resistance, superior to medium-acrylonitrile NBR and close to high-acrylonitrile NBR.Significantly better cold resistance, elasticity and processability than high-acrylonitrile rubber.Balanced performance in wear resistance, tear strength and compression set.Outstanding resistance to heat, fuel oil, lubricating oil and solvents.Suitable for long-term service in oilfields, automobiles, construction machinery, ships and other working conditions.Cost-effective and serves as the main general-purpose oil-resistant rubber for export markets.

NBR

Medium-high nitrile NBR is an oil-resistant synthetic rubber with balanced performance.

NBR

It offers excellent oil resistance, good elasticity and high wear resistance.

Basic Principles and System Composition

Basic Working Principle

Basic Principle

Medium high acrylonitrile NBR is produced via low-temperature free radical emulsion polymerization:Using butadiene and acrylonitrile as monomers, micelles are formed in the aqueous phase with emulsifiers, and copolymerization occurs under the action of a redox initiation system.By controlling the acrylonitrile ratio, the nitrile group content in the polymer is stabilized at 31%–35%, resulting in medium high acrylonitrile latex with balanced oil resistance and cold resistance.Solid rubber is finally obtained through post-treatment processes.

Overall System Composition

System Composition

Raw Material Preparation SystemButadiene, acrylonitrile, soft water, emulsifier, initiator, molecular weight regulator, terminator, antioxidant, coagulant. Polymerization Reaction SystemPre-emulsification unit, polymerization kettle, cooling system, nitrogen deoxidation system. Monomer Recovery SystemFlash degassing, stripping, rectification, monomer recycling and reuse. Post-treatment SystemLatex coagulation, water washing, dehydration, drying, bale pressing, packaging. Automatic Control & Environmental Protection SystemDCS control system, wastewater treatment, VOCs recovery, refrigeration system.

Basic Principles and System Composition

Raw Material Purification and PreparationButadiene and acrylonitrile are rectified to remove impurities; aqueous phase, oil phase and initiator solution are prepared separately. Pre-emulsificationThe oil and aqueous phases are fed into an emulsifier and mixed to form a stable pre-emulsion. Low-temperature PolymerizationThe pre-emulsion is introduced into the polymerization kettle, deoxidized with nitrogen, and polymerized at 5–15°C. Conversion is controlled, and a terminator is added to stop the reaction once the required index is achieved. Unreacted Monomer RecoveryFlash evaporation to remove butadiene → stripping to remove acrylonitrile → rectification and recycling. Latex CoagulationThe latex is transferred to a coagulation kettle, where brine is added to break the emulsion and precipitate rubber particles. Washing and DewateringRubber particles are thoroughly washed to remove salts → dewatered by an extrusion dewatering machine. Drying, Forming and PackagingLow-temperature drying in an expansion dryer → cooling → baling → metal detection → export-standard packaging → warehousing and delivery.