Sealing Ring Materials and Applications

I. NBR (Nitrile Rubber) Sealing Ring

Suitable for petroleum-based hydraulic oils, glycol-based hydraulic oils, diester-based lubricants, gasoline, water, silicone grease, silicone oil, and other media. It is currently the most widely used and lowest-cost rubber seal. Not suitable for polar solvents such as ketones, ozone, nitro hydrocarbons, MEK, and chloroform. Typical operating temperature range: -40°C to 120°C.

II. HNBR (Hydrogenated Nitrile Rubber) Sealing Ring

Offers good corrosion resistance, tear resistance, and compression set resistance, with excellent resistance to ozone, sunlight, and weathering. Better abrasion resistance than NBR. Suitable for washing machinery, automotive engine systems, and refrigeration systems using the new environmentally friendly refrigerant R134a. Not recommended for use in alcohols, esters, or aromatic solutions. Typical operating temperature range: -40°C to 150°C.

III. SIL (Silicone Rubber) Sealing Ring

Excellent heat resistance, cold resistance, ozone resistance, and atmospheric aging resistance. Good insulation properties. However, tensile strength is lower than general rubber, and it is not oil-resistant. Suitable for household appliances such as electric water heaters, irons, and microwave ovens. Also suitable for various items that come into contact with the human body, such as kettles and water dispensers. Not recommended for most concentrated solvents, oils, concentrated acids, or sodium hydroxide. Typical operating temperature range: -55°C to 250°C.

IV. VITON (Fluorocarbon Rubber) Sealing Ring

High-temperature resistance superior to silicone rubber, with good weather resistance, ozone resistance, and chemical resistance, but poor cold resistance. Resistant to most oils and solvents, especially acids, aliphatic hydrocarbons, aromatic hydrocarbons, and animal and vegetable oils. Suitable for sealing requirements in diesel engines, fuel systems, and chemical plants. Not recommended for use with ketones, low-molecular-weight esters, or nitro-containing mixtures. Typical operating temperature range: -20°C to 250°C.

V. FLS (Fluorosilicone Rubber) Sealing Ring

Combines the advantages of fluorocarbon rubber and silicone rubber, offering excellent oil resistance, solvent resistance, fuel oil resistance, and high/low temperature resistance. Resistant to oxygen-containing compounds, aromatic hydrocarbon solvents, and chlorine-containing solvents. Generally used in aviation, aerospace, and military applications. Not recommended for exposure to ketones or brake fluids. Typical operating temperature range: -50°C to 200°C.

VI. EPDM (Ethylene Propylene Diene Monomer) Rubber Sealing Ring

Good weather resistance, ozone resistance, water resistance, and chemical resistance. Can be used with alcohols and ketones, as well as for sealing in high-temperature steam environments. Suitable for sanitary equipment, automotive radiators, and automotive brake systems. Not recommended for food applications or exposure to mineral oils. Typical operating temperature range: -55°C to 150°C.

VII. CR (Chloroprene Rubber) Sealing Ring

Good resistance to sunlight and weathering. Resistant to refrigerants such as dichlorodifluoromethane and ammonia, as well as dilute acids and silicone-based lubricants, but swells significantly in mineral oils with low aniline points. Tends to crystallize and harden at low temperatures. Suitable for various environments exposed to air, sunlight, ozone, and various flame-resistant and chemical-resistant sealing applications. Not recommended for use with strong acids, nitro hydrocarbons, esters, chloroform, or ketones. Typical operating temperature range: -55°C to 120°C.

VIII. IIR (Butyl Rubber) Sealing Ring

Excellent airtightness, good heat resistance, sunlight resistance, ozone resistance, and insulation properties. Good resistance to polar solvents such as alcohols, ketones, and esters, and can be exposed to animal and vegetable oils or oxidizable substances. Suitable for chemical-resistant or vacuum equipment. Not recommended for use with petroleum solvents, kerosene, or aromatic hydrocarbons. Typical operating temperature range: -50°C to 110°C.

IX. ACM (Acrylic Rubber) Sealing Ring

Good oil resistance, high-temperature resistance, and weather resistance, but mechanical strength, compression set, and water resistance are slightly inferior. Generally used in automotive transmission systems and power steering systems. Not suitable for hot water, brake fluids, or phosphate esters. Typical operating temperature range: -25°C to 170°C.

X. NR (Natural Rubber) Sealing Ring

Good abrasion resistance, elasticity, tensile strength, and elongation. However, it ages easily in air, becomes sticky when heated, swells and dissolves in mineral oil or gasoline. Alkali-resistant but not strong acid-resistant. Suitable for use in automotive brake fluids, ethanol, and other liquids containing hydroxide ions. Typical operating temperature range: -20°C to 100°C.

XI. PU (Polyurethane Rubber) Sealing Ring

Polyurethane rubber offers excellent mechanical properties, with far superior wear resistance and high-pressure resistance compared to other rubbers. Aging resistance, ozone resistance, and oil resistance are also quite good, but it is prone to hydrolysis at high temperatures. Generally used in high-pressure, high-wear sealing applications such as hydraulic cylinders. Typical operating temperature range: -45°C to 90°C.