Cork Rubber Gasket

Kaxite KXT-1720 cork rubber gaskets are supplied as custom die-cut gaskets or composite parts made to drawing, dimension list or physical sample. The cork-and-CR construction is a balance point in the rubber gasket range: softer and more compressible than a solid rubber gasket, harder and more oil-resistant than a cork sheet gasket. Where the joint needs maximum compressibility in dry service, cork sheet is the cheaper alternative; where the joint carries oil or fuel at higher pressure, a solid rubber or nitrile (NBR) gasket is the correct material instead.

The data below covers the standard KXT-1720 cork rubber compound. Non-standard thicknesses, densities and coloured grades (for identification or food-contact) are available on request. Include the required thickness, gasket OD / ID / bolt circle or drawing, and quantity in the enquiry for accurate pricing and lead time.

The three cork-family gasket materials are not interchangeable — each has a specific range where it outperforms the others. The distinction matters most in transformer, switchgear and hydraulic sealing, where getting the compressibility and the oil resistance wrong is the difference between a dry joint and a leak.

Cork sheet — solid cork with a natural binder — is the most compressible and the most economical, but it has low tensile strength and low oil resistance. It is the right choice for dry, low-pressure flange joints and for general industrial compressibility needs. Where the joint sees any oil at all, cork sheet alone is the wrong material.

Cork rubber (KXT-1720, this page) — cork granules bonded with CR — combines the compressibility of cork with the resilience, oil tolerance and weather resistance of neoprene. The CR binder is what allows it to be specified in transformer oil, hydraulic fluid and outdoor service. It is the practical upgrade from cork sheet when the joint has oil, weather, or bolt-load variability.

Solid rubber — a solid rubber gasket such as black natural rubber, NBR, neoprene or silicone — is the strongest and most oil- or temperature-resistant option, but it has minimal compressibility and demands flatter flange surfaces. It is the right choice for higher-pressure and higher-temperature joints where bolt load and flange finish can support a solid rubber gasket.

KXT-1720 is specified where the joint needs to be compressible (so it seals against stamped or cast flange surfaces without high bolt load) but also oil- and weather-tolerant (so it survives the operating environment). That combination is why the same material appears in transformer covers, switchgear enclosures, hydraulic equipment and outdoor sealing applications — four settings with different media but the same material compromise.

Transformers and electrical switchgear — cork rubber is the traditional gasket material for transformer tank covers, inspection covers and switchgear enclosure flanges. The cork provides the compressibility needed to seal against large stamped steel covers, while the CR binder tolerates transformer oil and resists the UV and ozone exposure of outdoor substations.

Hydraulic equipment and heavy industrial machinery — cork rubber gaskets are used on hydraulic tank covers, gearbox inspection covers, pump housing flanges and industrial machinery enclosures, where the flange surfaces are not high-precision machined and the compressibility of the cork rubber helps seal the joint under moderate bolt load.

Outdoor sealing — the CR binder resists atmospheric attack — UV, ozone, moisture and temperature cycling — which is why KXT-1720 is specified in outdoor enclosures, HVAC units, and outdoor equipment flanges where a natural rubber gasket would age and crack.

For joints beyond the KXT-1720 range — higher pressure, higher temperature, or higher oil load — see the solid rubber rubber gasket range, or the nitrile (NBR) gasket range for continuous oil and fuel service.

KXT-1720 is manufactured at Kaxite’s Ningbo facility and supplied factory-direct for OEM, MRO, project and distribution procurement. Standard sheet is held for fast die-cutting; custom die-cut gaskets, composite parts (cork rubber bonded to metal insert or to another elastomer layer) and non-standard densities are made to drawing or physical sample. For buyers consolidating a transformer or switchgear gasket package, KXT-1720 can be combined with the cork sheet range and solid rubber gasket ranges in a single shipment, so that different flange requirements in the same plant are supplied together with consistent documentation.