Abstract: A composite, dynamic seal suitable for use in a high temperature environment and method of making same. The dynamic seal includes a resilient, generally ring-shaped seal body having a first layer formed of a first resilient sealing material and a second layer formed of a second resilient sealing material. The first and second layers are preferably molded and cured together simultaneously and chemically cross-linked to each other. The first resilient sealing material is selected for its wear resistant dynamic properties and the second resilient sealing material is selected for its compression set resistant properties. Preferably, the first resilient sealing material is tetrafluoroethylene and propylene copolymer and the second resilient sealing material is fluorocarbon rubber. The first and second resilient sealing materials have compatible cure systems, preferably peroxide cure systems.

Abstract: A high performance rock bit journal seal is formed from a composite material comprising an elastomeric material and a nonelastomeric polymeric material. The polymeric material is preferably in the form of fibers compiled or woven into a sheet. The elastomeric material may include one or more lubricant additives. The composite seal material comprises a number of repeating sheets of polymeric fabric that are bonded together with the elastomeric material. The seal can either be formed entirely of the composite seal material or partially of the composite material, in which case it is preferred that the seal wear or dynamic surface be formed from the composite material and the remaining portion of the seal be formed from an elastomeric material. The seal can be used as a primary journal seal, or as a secondary journal seal in a dual seal bit.

Abstract: A high performance rock bit journal seal is formed from a composite material comprising an elastomeric material and a nonelastomeric polymeric material. The polymeric material is preferably in the form of fibers woven into a sheet. The elastomeric material includes at least one lubricant additive. The composite seal material comprises a number of repeating sheets of polymeric fabric that are bonded together with the elastomeric material. In one embodiment, the seal includes a body formed entirely from the composite material, in which case both the static and dynamic seal surfaces are the same. In another embodiment, the seal includes a first body portion formed from the composite material, and a remaining body portion formed from a noncomposite elastomeric seal material.