Abstract: A gasket which contains microspheres which expand inside the gasket sheet material after the gasket sheet is formed. Such gaskets are especially useful to provide a seal against fluid leaks at significantly lower pressures due to the presence of the microspheres. Some microspheres can expand during use.

Abstract: A gasket is described which contains microspheres which expand inside the gasket sheet material after the gasket sheet is formed. Such gaskets are especially useful to provide a seal against fluid leaks at significantly lower pressures due to the presence of the microspheres. Some microspheres can expand during use.

Abstract: An asbestos-free gasket forming composition is disclosed. The composition is preferably produced by removing water from an aqueous furnish composition comprising phenolic fibers, aromatic polyamide fibers, an inorganic or cork filler, a synthetic rubber binder, and a water insoluble hydroxide produced from a soluble salt selected from the group consisting of aluminum salts, ferric salts and stannic salts, by reaction with a sufficient amount of an alkaline hydroxide to provide a furnish pH within the range of from about 6 to about 10, and preferably of from about 7 to 8.