Nitrile, hydrogenated

Fig. 1. SAE J200 Classification system for ASTM No. 3 oil where in volume swell nr = no requirement. EPDM is ethylene—propylene—diene monomer HR, butyl mbber SBR, styrene—butadiene mbber NR, natural mbber VMQ, methyl vinyl siUcone CR, chloroprene FKM, fluoroelastomer FVMQ, fluorovinyl methyl siUcone ACM, acryUc elastomers HSN, hydrogenated nitrile ECO, epichlorohydrin and NBR, nitrile mbber.

Two suppliers to the U.S. market are Bayer and Nippon Zeon. The estimated volume used in the United States is 500 700 t/yr. Hydrogenated nitrile mbber (HSN or HNBR) compounds compete with EKM, EVMQ, ECO, ACM, and high ACN content nitrile mbbers. Big applications include automotive timing belts, blowout preventors, drill pipe protectors, and numerous oil and fuel pump components. 

Table 6. World Production Facilities for Hydrogenated Nitrile Rubber ...

S. Hayashi, M. Oyama, K. Hashimoto, and T. Nakagawa, "New Improved Low Temperature Hydrogenated Nitrile Rubber (HNBR)," paper presented at theH.CA. Racbber Division Meeting, Detroit, Mich., Oct. 8—11,1991. 

Hydrogenated nitrile rubbers were introduced in the mid-1980s as Therban by Bayer. The initial grade had an acrylonitrile content of only 17% instead of approx. 34% in conventional NBR. Whilst non-sulphur-curing systems such as the use of peroxides with triallyl cyanurate or isocyanurate are necessary, the saturated rubber has a number of advantages over NBR. These include improved... 

Polynorbomene (PNR), polyoctenamer and hydrogenated nitrile rubber (HNBR)—this chapter... 

Footnotes (a) Gaskets are also available in other materials, such as hydrogenated nitrile, neoprene, butyl rubber, hypalon, silicon rubber to meet various application requirrnents. (b) Viton is a Du Pont Co. trademark for a series of fluoroelastotners based on the copolymer ofvinylidene fluoride and hexafluoropropylene. 

This chapter mainly aims at describing the various methods and processes developed for hydrogenation of nitrile rubber. The characterization, physical properties, and application of hydrogenated nitrile rubber are also discussed. Another small section on hydroformylation of nitrile rubber has been included. 

The coefficients a, b, and c for hydrogenation were obtained from the literature [13] and those for nitrile and hydrogenated nitrile were calculated from a group contribution method reported by Rihani and Doraiswami [14]. All the necessary data are listed in Table 1. The integration constant / and AHq have been calculated by incorporating the values of AG° and AH° at 298 K in Eqs. (3) and (4). The equilibrium constant at atmospheric pressure and various temperature has been calculated according to the relationship ... 

The value of AG° at various reaction temperatures and corresponding Kp values are reported in Table 2. It can be understood from Table 2 that the formation of hydrogenated nitrile rubber from nitrile rubber is thermodynamically feasible. 

The research in this area has a great potential from scientific and technological aspects and requires further exploration. However, the reported attempts are a welcoming endeavor to hydrogenate nitrile rubber in latex form. 

Hydrogenated nitrile rubber is much more stable than NBR at elevated temperature. Bhattacharjee et al. [134] performed a high-temperature degradation (30-800°C) of HNBR and NBR in nitrogen atmosphere... 

Bhowmick A.K. and Inoue T., Stmeture development during dynamic vulcanization of hydrogenated nitrile mbber/nylon blends, J. Appl. Polym. Sci., 49, 1893, 1993. 

The correlation in Figure 13.1 allows the prediction of 8 required for a cross-linked rabber with a desired oil resistance. For example, the structure of EPDM has to be modified in such a way that a 8 outside the range of 13.5-18.0 (J/cm ) is achieved in order to have an oil swell similar to HNBR20 (hydrogenated nitrile mbber with 20% acrylonitrile). 

Elastomer types used successfully in these areas are natural rubber (NR), polychloroprene (CR), and nitrile rubber (NBR), and hydrogenated nitrile rubber (HNBR), where oil resistance is also required. 

W02005/080456 Al, Lanxess Inc. Process for the preparation of low molecular weight hydrogenated nitrile rubber EP2028194 Al, Lanxess Deutschland GmbH Metathesis of nitrile rubbers in the presence of transition metal complex catalysts Press release Lanxess - New York Conference, New York City, USA, Monday August 28, 2006, Address by Dr. Ulrich Koemm LANXESS Concepts in Rubber ... 

The residual carbon-carbon double bond in nitrile butadiene rubber (NBR) can be catalytically hydrogenated to yield its tougher and more stable derivative, hydrogenated nitrile butadiene rubber (HNBR).2 This class of specialty elastomer was developed to expand the range of operating environments possible for nitrile butadiene rubber NBR in environments that expose the rubber to chemical and thermal attack. 

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