RU23™ - a high performing fluoroelastomer!

Seal Engineering’s RU23™ is a high performing fluoroelastomer designed for the most demanding sealing applications. RU23™ has gained acceptance in the oilfield and chemical processing sealing industries to replace expensive materials like FFKM, while providing greater chemical compatibility compared to speciality FKM grades.

Therefore, the compound is a bridge between FFKM perfluoroelastomers and FKM elastomers. While officially classified as FEPM by ASTM D1418, the performance characteristics of  RU23™ (based on Chemours’ Viton® Extreme ETP-600S) combine the best attributes of all fluorinated elastomers.

In chemically aggressive applications, where FKM is not an option, RU23™ is the fluoroelastomer of choice. RU23™ is compounded using a dedicated peroxide curative system. In order to secure the broadest possible chemical resistance, the elastomer has been formulated without employing metal oxides. No volatile ingredients are present in the produced parts.

While standard FKM polymer structures are susceptible to chemical attack by caustic and amine-containing media, the unique molecular architecture provides ETP with inherent resistance to high pH fluids. Owing to the higher fluorine content, RU23™ also outperforms TFE/P (Aflas®) in performance following exposures to crude oil and aromatic hydrocarbons. 


Quick facts on RU23™:

  • Very high temperature resistance up to 230°C with excursions to 250°C (compares favorably with high-fluorine FKM and multipurpose FFKM) 
  • Low temperature flexibility down to -10°C with conditional sealability secured down to -20°C (outperforms high-fluorine FKM, TFE/P and multipurpose FFKM)
  • Nominal 85 Shore A durometer hardness provides an optimized balance between mechanical properties, sealing performance and chemical resistance over the whole service window
  • Excellent retention of mechanical properties, securing long service lives at elevated temperatures and in hostile environments (including ozone and UV radiation)
  • Good compression set resistance and long-term sealing capabilities at elevated temperatures, high pressures and in extreme chemical conditions
  • Exceptional resistance to a broad range of aggressive chemicals, including aromatic hydrocarbons (benzene, toluene, xylene), crude oil, high concentrations of sour gases (H2S, CO2), mineral and organic acids (hydrochloric, acetic, formic), heavy halide brines (ZnBr2, CaBr2), alcohols and glycols (methanol, MEG), ketones (acetone, MEK, MIBK), aldehydes (formaldehyde, glutaraldehyde), complex solvent mixtures, biocides (outperforms FKM, comparable to FFKM)
  • Inherent resistance to chemical attack and volume swell in highly caustic and amine-containing media (high pH), including Cs/K formate brines, HFC (water-glycol) hydraulic fluids, corrosion inhibitors (outperforms FKM, comparable to FFKM) 
  • Good resistance to hydraulic fluids based on phosphate ester chemistry (various lines of Skydrol®)
  • Full compatibility to virtually all synthetic and biobased environmentally acceptable lubricants (EAL) and hydraulic fluids (HEES, HEPG, HEPR, HETG)
  • Best-in-class resistance to hot water, superheated steam as well as other geothermal and EOR chemistries owing to optimized compound formulation (no metal oxides);
  • Reduced thermal expansion compared to FFKM, giving OEM designers greater freedom for proper seal groove designs
  • Exceptional surface quality of molded parts, offering superior sealing function
  • Very low outgassing in use under high vacuum conditions
  • High bondability to metal and other substrates (due to dedicated bonding promotion technologies), enabling to produce composite parts and assemblies
  • Available in a range of molded and machined shapes, including static and dynamic seals, gaskets, diaphragms, bellows, bonded seals, etc.


The combination of high-temperature performance, low-temperature flexibility, mechanical and sealing characteristics, and exceedingly broad chemical resistance has allowed RU23™ seals to operate exceptionally well under extreme conditions in the oil and gas exploration and chemical processing applications.

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