Sealing ring

Application of Materials

NBR nitrile rubber sealing ring: Suitable for use in petroleum-based hydraulic fluids, glycol-based hydraulic fluids, diester lubricants, gasoline, water, silicone greases, silicone oils, and other media. It is currently the most widely used and lowest-cost rubber sealing element. Not suitable for polar solvents such as ketones, ozone, nitrohydrocarbons, MEK, and chloroform. The typical operating temperature range is –40 to 120 °C.

HNBR hydrogenated nitrile rubber sealing ring: It exhibits excellent resistance to corrosion, tearing, and compressive deformation, with good ozone, sunlight, and weathering resistance. It offers superior abrasion resistance compared to nitrile rubber. It is suitable for use in washing machinery, automotive engine systems, and refrigeration systems that employ the environmentally friendly refrigerant R134a. However, it is not recommended for exposure to alcohols, esters, or aromatic solvents. Its typical service temperature range is –40 to 150 °C.

SIL silicone rubber sealing ring: It exhibits excellent resistance to heat, cold, ozone, and atmospheric aging. It also boasts superior electrical insulation properties. However, its tensile strength is lower than that of typical rubbers, and it lacks oil resistance. It is suitable for household appliances such as electric water heaters, irons, and microwave ovens. Additionally, it is appropriate for various products that come into contact with the human body, including kettles and water dispensers. It is not recommended for use in most concentrated solvents, oils, strong acids, or sodium hydroxide solutions. Its typical service temperature range is –55 to 250 °C.

VITON fluororubber sealing ring: It exhibits superior high-temperature resistance compared to silicone rubber, along with excellent weatherability, ozone resistance, and chemical resistance; however, its cold‑temperature performance is poor. It is resistant to most oils and solvents, particularly acids, aliphatic hydrocarbons, aromatic hydrocarbons, and animal and vegetable oils. It is suitable for sealing applications in diesel engines, fuel systems, and chemical plants. Use is not recommended with ketones, low‑molecular‑weight esters, or nitrate‑containing mixtures. Its typical service temperature range is –20 to 250 °C.

FLS fluorosilicone rubber sealing ring: Its performance combines the advantages of both fluororubber and silicone rubber, exhibiting excellent resistance to oils, solvents, fuel oils, and extreme temperatures. It is resistant to oxygenated compounds, aromatic hydrocarbon solvents, and chlorinated solvents. It is typically used in aerospace and military applications. Exposure to ketones and brake fluids is not recommended. Its typical service temperature range is –50 to 200 °C.

EPDM (ethylene propylene diene monomer) rubber sealing ring: It exhibits excellent weather resistance, ozone resistance, water resistance, and chemical resistance. It is suitable for use with alcohols and ketones, as well as for sealing in high‑temperature steam environments. Applications include bathroom fixtures, automotive radiators, and automotive brake systems. It is not recommended for food‑contact applications or for exposure to mineral oils. The typical service temperature range is –55 to 150 °C.

CR neoprene sealing ring: It exhibits excellent resistance to sunlight and weathering. It is resistant to refrigerants such as dichlorodifluoromethane and ammonia, as well as to dilute acids and silicone‑based lubricants; however, it swells significantly in mineral oils with low aniline points. At low temperatures, it tends to crystallize and harden. It is suitable for a wide range of applications exposed to atmospheric conditions, sunlight, and ozone, as well as for sealing environments requiring flame resistance and chemical corrosion resistance. It is not recommended for use with strong acids, nitrohydrocarbons, esters, chloroform, or ketones. Its typical service temperature range is −55 to 120 °C.

IIR butyl rubber sealing ring: It exhibits excellent airtightness, outstanding resistance to heat, sunlight, and ozone, and superior electrical insulation properties. It demonstrates strong resistance to polar solvents such as alcohols, ketones, and esters, and can be exposed to vegetable and animal oils or oxidizable substances. It is well suited for applications involving chemical resistance or vacuum equipment. However, it is not recommended for use in conjunction with petroleum solvents, kerosene, or aromatic hydrocarbons. Its typical service temperature range is –50 to 110 °C.

ACM Acrylate Rubber Seal Ring: It exhibits excellent resistance to oils, with superior high-temperature and weathering performance; however, its mechanical strength, compression set, and water resistance are somewhat limited. It is typically used in automotive transmission and power‑steering systems. It is not suitable for use with hot water, brake fluid, or phosphate esters. Its typical service temperature range is –25 to 170 °C.

NR natural rubber sealing ring: It exhibits excellent wear resistance, elasticity, tensile strength, and elongation. However, it is prone to aging in air, becomes tacky when exposed to heat, and swells or dissolves readily in mineral oil or gasoline. It is alkali‑resistant but not resistant to strong acids. It is suitable for use in automotive brake fluids, ethanol, and other liquids containing hydroxide ions. Its typical service temperature range is –20 to 100 °C.

PU polyurethane rubber sealing ring: Polyurethane rubber exhibits excellent mechanical properties, with wear resistance and high-pressure resistance far surpassing those of other elastomers. It also demonstrates outstanding resistance to aging, ozone, and oils; however, it is prone to hydrolysis at elevated temperatures. It is commonly employed in high-pressure, wear‑resistant sealing applications, such as hydraulic cylinders. Its typical service temperature range is –45 to 90 °C.

Metal rubber sealing ring: Made from stainless steel wire and containing no rubber, it boasts exceptional performance characteristics. For instance, it maintains reliable operation under conditions such as high vacuum, extreme temperatures, intense radiation, and various corrosive environments. The sealing ring’s outer layer is crafted from materials like stainless steel, copper, or polytetrafluoroethylene, depending on the application, while a metal‑rubber core serves as the liner, offering superior sealing strength, excellent sealing performance, and reusability. The core of the sealing ring is manufactured with varying wire diameters and densities, making it suitable for a wide range of pressure applications. Its typical operating temperature range spans from –80°C to 800°C. Due to its high manufacturing costs, this type of sealing ring commands a premium price; however, its outstanding performance and versatility across diverse service environments have earned widespread recognition.

Product Performance

In addition to meeting the general requirements for sealing‑ring materials, sealing rings must also satisfy the following conditions:

(1) Highly elastic and resilient;

(2) Adequate mechanical strength, including tensile strength, elongation at break, and tear resistance.

(3) It exhibits stable performance, is resistant to swelling in the medium, and has a low thermal shrinkage effect (Joule effect).

(4) Easy to process and form, while maintaining precise dimensions.

(5) Does not corrode the contact surface and does not contaminate the medium, etc.

The most suitable and widely used material that meets the aforementioned requirements is rubber; therefore, sealing rings are predominantly manufactured from rubber. A wide variety of rubber types exist, with new formulations continually being developed. When designing and selecting materials, it is essential to understand the properties of each type and make an informed choice.