US Patent 7306665 Friction material composition and friction material using the composition

A friction material composition containing a fibrous material, a binder and a friction adjusting agent, wherein the friction adjusting agent is secondary aggregates of an activated alumina being spherical and having a diameter of 10 to 300 μm, or an activated alumina having a specific surface area of 100 to 400 m2/g and an average particle diameter of 1 to 200 μm. The composition can be used for producing a friction material which exhibits significant improvement with respect to fading phenomenon, without adversely affecting its characteristics of attacking to a disc rotor, which is the article mating therewith, and without marked reduction of the friction coefficient at an elevated temperature, and is capable of controlling the thickness of the sliding film formed on a frictionally sliding face and preventing a high frequency noise (grabbing chatter).