Provided axe porous titanate compound particles capable of giving excellent fade resistance when used in a friction material, a resin compound and a friction material each containing the porous titanate compound particles, and a method for producing the porous titanate compound particles. Porous titanate compound particles are each formed of titanate compound crystal grains bonded together and have a cumulative pore volume of 5% or more within a pore diameter range of 0.01 to 1.0 μm.

A friction material composition includes a binder, organic filler, inorganic filler and fiber reinforcement, and does not contain copper or contains copper in an amount of 0.5 mass % or less. The inorganic filler is one or more selected from y alumina having an average particle size of 10 nm to 50 μm, dolomite having an average particle size of 1 to 20 μm, calcium carbonate having an average particle size of 1 to 20 μm, magnesium carbonate having an average particle size of 1 to 20 μm, manganese dioxide having an average particle size of 1 to 20 μm, zinc oxide having an average particle size of 10 nm to 1 μm, magnetite having an average particle size of 1.0 μm or less, cerium oxide having an average particle size of 0.5 to 5 μm, and zirconia having an average particle size of 5 to 50 nm.

A friction material composition that does not contain copper, which has a high environmental load, or containing copper in such small amount as to be not more than 0.5 mass % and that enables decrease in brake vibration in braking at high temperatures when used in a friction material such that for an automobile disc brake pad, is provided. A friction material obtained by molding the friction material composition is also provided. The friction material composition contains a binder, an organic filler, an inorganic filler, and a fibrous base material, and the friction material composition contains no copper as an element or contains not more than 0.5 mass % of copper, and also contains 2 to 5 mass % of steel fibers that have fiber lengths of 2500 μm or less.

A wet friction material for use in a wet clutch includes a friction interfacing surface for experiencing frictional engagement with an opposed surface in the presence of a lubricant. At least a portion of the friction interfacing surface comprises fibrillated nanofibers, which define a nanofibrous web, and friction adjusting particles held by the nanofibrous web. A cured resin may adhere the fibrillated nanofibers and the friction adjusting particles to provide structural support for the friction material.

[OBJECT] The present invention provides a friction material used for a disc brake pad, which is able to secure the braking effectiveness and the wear resistance under the high speed and high load braking conditions while satisfying laws and regulations relating to the required amount of the content of the copper component.

[MEANS TO SOLVE THE PROBLEM] A friction material used for a disc brake pad, which is manufactured by forming a non-asbestos organic friction material composition, in which the friction material composition contains 1-15 weight % of ferrous sulfide (FeS) particles relative to the total amount of the friction material composition as a lubricant, and the total amount of the copper component involved in the friction material composition is less than 5 weight % relative to the total amount of the friction material composition. Furthermore, it is preferable to contain 0.3-5 weight % of flaky graphite particles with 1-100 μm of average particle diameter or the aggregates thereof relative to the total amount of the friction material composition.

[OBJECT]

The present invention provides a friction material used for a disc brake pad, which is manufactured by forming a non-asbestos-organic (NAO) friction material composition, which is able to suppress an occurrence of noise just before a vehicle stops, while satisfying laws and regulations relating to the required amount of the content of the copper component.

[MEANS TO SOLVE THE PROBLEM]

The friction material for the disc brake pad is manufactured by forming the NAO friction material composition that is free of the copper component, the friction material composition practically does not include an iron component but includes 15-22 weight % of a non-whisker-like titanate, relative to the total amount of the friction material composition, as a titanate, 15-25 weight % of zirconium oxide with the average particle diameter of 1.0-4.0 μm, relative to the total amount of the friction material composition, as the inorganic friction modifier, and 4-6 weight % of cleavable mineral particles, relative to the total amount of the friction material composition, as the inorganic friction modifier.

A wet friction material includes a base including a matrix of fibers and filler particles embedded in the matrix of fibers; a binder embedded in an interior of the base; and a quaternary ammonium salt containing coating on an outer surface of the base. The quaternary ammonium salt containing coating can include a quaternary ammonium salt and a solution binder

The brake pad 10 includes a friction material 12 provided on the side of the disc 200 and a back plate 11 bonded to the friction material on the opposite side of the disc 200. A thickness of a peripheral region of the back plate on the side of a center of the disc is larger than a thickness of a peripheral region of the back plate on the side of an outer circumference of the disc. In the case where a minimum value of the thickness of the peripheral region of the back plate on the side of the center of the disc is defined as “h.sub.2 [mm]” and a maximum value of the thickness of the peripheral region of the back plate 11 on the side of the outer circumference of the disc is defined as “h.sub.1 [mm]”, h.sub.1 and h.sub.2 satisfy a relationship of “h.sub.2−h.sub.1<3”.

A friction material includes a fiber base material, a friction modifying material and a binder. The friction modifying material includes alumina particles including, as a main component, θ-alumina particles. The θ-alumina particles are contained in an amount of 1 mass % or more in the friction material.

A friction material composition of the present invention includes a fibrous base, a friction regulator, and a binder and has a copper content of 0.5 mass % or less in terms of copper element amount. The friction material composition contains regenerated cellulosic fibers as the fibrous base. In an embodiment of the friction material composition, the regenerated cellulose fiber has a fiber length of 2 mm to 20 mm.