Bonded Seals

KOK manufactures bonded seals, also known as sealing washers, for mechanical, hydraulic, and pneumatic systems requiring reliable static sealing under bolt head or fitting compression.

Bonded seals consist of a metal retaining washer with a bonded elastomer sealing element. When compressed, the elastomer provides a pressure-tight seal while the metal ring prevents over-compression and extrusion.

Functional Performance

KOK bonded seals are designed to provide:

• Reliable static sealing in threaded and bolted connections
• Resistance to hydraulic pressure and fluid leakage
• Controlled compression under tightening torque
• Long-term stability in oil, fuel, and air systems

The metal-to-elastomer bonding process is controlled to ensure consistent adhesion strength and dimensional accuracy.

Product Variants

KOK’s bonded seal range includes:

• Self-centering bonded seals
• Rubber-covered bonded seals
• Double-ring bonded seals
• Standard and custom configurations

Dimensional Range

4 mm – 75 mm

Custom dimensions and profiles are supported based on customer specifications.

Material selection is aligned with media compatibility, temperature range, and operating pressure.

Application Scope

KOK bonded seals are used in:

• Hydraulic fittings
• Pneumatic systems
• Mechanical fastening interfaces
• Industrial fluid power assemblies