other names: Nitrile butadiene rubber; Nitrile rubber; NBR rubber; Acrylonitrile butadiene rubber; Nitrile butadiene rubber; Nitrile rubber
Short designation: NBR
Meister Lucius und Brüning AG (Höchst) and Badische Anilin- und Sodafabrik AG (Ludwigshafen) with the intention of abandoning competing business activities in the future and jointly exploiting the scientific and economic potential. Within this association, which operated as Interessengemeinschaft Farbenindustrie Aktiengesellschaft with the official abbreviated name I.G. Farbenindustrie AG, the focal points for product development and production were now located where the most favourable conditions for their realization offered themselves. For example, elastomer research was established at the Bayer plants in Leverkusen, where the chemists Walter Bock (1895-1948) and Eduard Tschunkur (1874-1946) had already developed styrene-butadiene rubber (SBR) in the late 1920s. Around 1930, Erich Konrad (1894-1975), who had taken over as head of the central rubber laboratory of I.G.Farbenindustrie in Leverkusen in 1927, and Eduard Tschunkur, together with Helmut Kleiner (1902-1987), synthesized acrylonitrile-butadiene rubber (NBR) here. Production of the synthetic rubber, which very soon became essential for armaments, began in 1934.
Acrylonitrile-butadiene rubber has remained an economically important synthetic rubber to this day, although, like all other synthetic rubber products, it does not have the important physical-technical properties of the natural product, namely shear-induced crystallization under spontaneous stress. For this reason, natural rubber has not lost its importance, for example in the production of aircraft tires (for more details, see Natural rubber).
Acrylonitrile-butadiene rubber is usually only referred to as nitrile rubber. Synthetic rubber is the co-polymer of acrylonitrile, the nitrile of acrylic acid (2-propenenitrile) and the doubly unsaturated hydrocarbon 1,3-butadiene, as shown in the following diagram, which does not take the steric conditions into account:
The proportions of both monomeric components in the macromolecule, which are marked in the above diagram with the indices k for acrylonitrile and m for 1,3-butadiene, largely determine the technical properties of the synthetic rubber. The acrylonitrile content is usually between 18 and 51 mass %. By varying the proportions of the two starting monomers and by selecting the other synthesis parameters, mainly the polymerization temperature, the desired properties of the end product can be preset very precisely.
By mixing different types of NBR, blending NBR with other elastomers to form blends, such as polyvinyl chloride (PVC) or styrene-butadiene rubber (SBR), and incorporating fillers, its properties can be further modified and optimally adapted to the intended application.
The majority of the nitrile rubber produced worldwide is consumed by the automotive supply industry, primarily for pneumatic tires, oil and fuel lines and compressed air hoses, but also for dirt traps and sound-absorbing mats, sealing elements and corrosion-reducing coatings for metal surfaces. Another major customer for synthetic rubber is the shoe industry, where it is used as a basic material for laboratory and medical nitrile gloves and for chemical-resistant textile finishes. Finally, nitrile rubber hoses are universally applicable in laboratories and technical plants as flexible media lines for liquids and gases. They are offered in many dimensions and technical designs.
Numerous nitrile rubber types comply with the regulations of the German Technical and Scientific Association for Gas and Water (DVGB) and are expressly approved for use in gas and water supply systems. Due to its low ohmic resistance values, however, NBR is not suitable as an electrical insulation material.
The reaction is temperature-controlled in aqueous suspension, whereby cold polymerization and hot polymerization yield differently cross-linked products. However, crosslinking can also be achieved by classical vulcanization with sulfur.
As a general rule, the elasticity of nitrile rubber decreases as the acrylonitrile content increases, and the associated reduction in its tendency to swell increases its stability against chemicals and solvents.
Nitrile rubber with equal proportions of acrylonitrile and butadiene has the highest resistance to oils and fuels. The gas permeability of nitrile rubber decreases with increasing acrylonitrile content. For all acrylonitrile-butadiene rubber types, it is still lower than the gas permeability of natural rubber (NR) and also of styrene-butadiene rubber (SBR).
The proportions of both monomeric components in the macromolecule, which are marked in the above diagram with the indices k for acrylonitrile and m for 1,3-butadiene, largely determine the technical properties of the synthetic rubber. The acrylonitrile content is usually between 18 and 51 mass %. By varying the proportions of the two starting monomers and by selecting the other synthesis parameters, mainly the polymerization temperature, the desired properties of the end product can be preset very precisely.
By mixing different types of NBR, blending NBR with other elastomers to form blends, such as polyvinyl chloride (PVC) or styrene-butadiene rubber (SBR), and incorporating fillers, its properties can be further modified and optimally adapted to the intended application.
General properties | Color black |
Density | 1.35 g to 1.50 g / cm3 |
Thermal properties | Operating temperature range – 30 °C to +120 °C |
Fire class UL 94 V-0 | Oxygen index (LOI) < 25 |
Electrical properties | Contact resistance 1.2 x 104 Ω – cm |
Mechanical properties | Shore hardness A up to 80 |
Elongation at break | 250 % to 350 % |
Tear strength | 7 MPa to 13 MPa |
Compression set |
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Alcohols
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resistant
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Aldehydes, esters, ketones
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volatile
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Aliphatic hydrocarbons
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resistant
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Gasoline and diesel fuel
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resistant
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aromatic hydrocarbons
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volatile
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Halogenated hydrocarbons
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volatile
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Hydraulic oils, mineral oils and greases
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resistant
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Diluted acids
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resistant
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Diluted alkaline solutions
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resistant
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Hot water
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resistant
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UV radiation and ozone
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volatile
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Yanimed is a brand of Yanimed LLC based in Delaware US. Under the brand name Yanimed we produce disposable protective gloves for medical and industrial use.
We are – the home of Medical Gloves.
