PU O-rings

PU (Polyurethane) O-rings are tough, durable seals known primarily for their exceptional abrasion resistance, tear strength, and chemical compatibility with specific hydraulic fluids. They offer high performance in demanding industrial applications where typical rubber O-rings might fail due to mechanical wear or high pressure.
Key Features and Properties
Material: PU (Polyurethane), a type of polymer known for its excellent physical properties that bridge the gap between rubber and plastic.
Temperature Range: Generally performs reliably from -40°C to +80°C (-40°F to +176°F), though some formulations can operate up to 100°C (212°F).
Mechanical Properties: This is where PU excels. It offers outstanding tensile strength, tear strength, and abrasion resistance. It also features good elasticity, resilience, and a high load-bearing capacity.
Hardness: Typically found in the 70 to 90 Shore A range, often harder than standard NBR O-rings, which aids in handling high pressure and preventing extrusion.
Durability: Excellent resistance to compression set and aging.
Chemical Compatibility
Resistant To:
Mineral oils and greases (good resistance).
Non-flammable hydraulic fluids (HFA, HFB, HFC types, which are water/glycol-based).
Ozone, UV radiation, and general weathering.
Aliphatic hydrocarbons (propane, butane).
Water (with specific grade limitations; long-term exposure in hot water can cause swelling).
Not Recommended For Use With:
Strong acids, strong alkalis, and hot water/steam.
Ketones, esters, aldehydes, and chlorinated solvents.
Aromatic hydrocarbons (benzene, toluene).
Typical Applications
Due to their robust mechanical properties and specific chemical resistance profile, PU O-rings are used in heavy-duty applications:
Hydraulic and Pneumatic Systems: Widely used in hydraulic cylinder seals, piston seals, and rod seals where high pressure and abrasive wear are a concern.
Heavy Machinery: Essential in construction and mining equipment, agricultural machinery, and industrial presses that operate under demanding, high-load conditions.
Material Handling: Used in various components in lifting equipment and conveyor systems for durability.