In relation to the NAO friction material free of copper component, this invention is to provide the friction material that prevents the occurrence of metal catch while securing sufficient wear resistance. In the friction material manufactured by forming the NAO friction material composition which is free of copper component, the above-described friction material composition does not contain metal simple substance or alloy and contains, as the lubricant, metal sulfide having 600 centigrade or higher decomposition temperature to be decomposed into metal and sulfur, 2.0-5.0 weight % of graphite and a zirconium silicate as an abrasive material. Here, the metal sulfide is not a molybdenum disulfide or a tungsten disulfide. Especially, the content of the metal sulfide is preferably 0.5-2.0 weight % relative to the total amount of the friction material composition.

An asbestos-free friction material includes inorganic and/or organic and/or metallic fibers, at least one binder, at least one friction modifier or lubricant, at least one filler or abrasive and a carbonaceous material constituted by a microstructure. The microstructure is in the form of flakes or scales of micrometric planar dimensions and of nanometric thickness consisting of a substantially pure graphene mono- or multilayers, preferably pre-blended with at least part of the organic binder.

A non-asbestos frictional material composition is provided, which is capable of provide a frictional material with low environmental load and with excellent friction coefficient, anti-crack properties, and abrasion resistance compared with conventional ones. Furthermore, a frictional material and a friction member formed by using this non-asbestos frictional material composition are provided. The non-asbestos frictional material composition containing a binder, an organic filler, an inorganic filler, and a fiber base material, includes: copper in a content of 5 mass % or less as a copper element; a metal fiber other than a copper fiber and a copper alloy fiber in a content of 0.5 mass % or less; cashew dust in a content of 1.5-4.5 mass % as the organic filler; zirconium oxide with a particle size of 30 m or less in a content of 30-45 mass % but not containing zirconium oxide with a particle size of more than 30 m as the inorganic filler.

Method for manufacturing an asbestos-free friction material having as component materials inorganic and/or organic and/or metallic fibers, at least one organic binder, at least one friction modifier or lubricant and at least a filler or abrasive. The raw components of the friction material are mixed together to obtain a raw mixture which is then molded to obtain a block or layer of friction material. The mixing step includes a first step of hot blending of at least part of the organic binder with at least part of the other components of the friction material by a rolling mill blender that is open to atmospheric pressure at a temperature lower than the polymerization temperature of the organic binder but greater than or equal to its softening temperature, in order to obtain a semifinished solid product. A second step of grinding the semifinished solid product reduces the product to a powder.

A friction material, such as those belonging to the NAO or LS classes. The friction material is substantially free from copper and includes non-spherical particles in the form of powders and/or fibres each constituted by a preferably ferrous metallic core and by an at least partial coating of core formed at least partially or totally by tin and/or tin compounds, such as intermetallic FeSn compounds.

A friction material, such as those belonging to the NAO or LS classes. The friction material is substantially free from copper and includes non-spherical particles in the form of powders and/or fibers each constituted by a preferably ferrous metallic core and by an at least partial coating of core formed at least partially or totally by tin and/or tin compounds, such as intermetallic FeSn compounds.

A non-asbestos frictional material composition is provided, which is capable of provide a frictional material with low environmental load and with excellent friction coefficient, anti-crack properties, and abrasion resistance compared with conventional ones. Furthermore, a frictional material and a friction member formed by using this non-asbestos frictional material composition are provided. The non-asbestos frictional material composition containing a binder, an organic filler, an inorganic filler, and a fiber base material, includes: copper in a content of 5 mass % or less as a copper element; a metal fiber other than a copper fiber and a copper alloy fiber in a content of 0.5 mass % or less; cashew dust in a content of 1.5-4.5 mass % as the organic filler; zirconium oxide with a particle size of 30 m or less in a content of 30-45 mass % but not containing zirconium oxide with a particle size of more than 30 m as the inorganic filler.

To provide a low-cost friction material which is able to secure the required braking performance, the fading resistance, the wear resistance, and the adhesive strength between the friction material and the back plate while satisfying laws and regulations relating to the required amount of the content of the copper component contained therein. The friction material for the disc brake pad which is manufactured by forming a non-asbestos-organic (NAO) friction material composition that includes no copper component, in which the friction material composition includes no titanate but includes (a) 8-15 volume % of an inorganic friction modifier having the average particle diameter of 0.5-20 m and the Mohs hardness of 5-8 relative to a total amount of the friction material composition, (b) 1-3 volume % of a porous inorganic friction modifier having a micro porous structure relative to the total amount of the friction material composition, and (c) 5-10 volume % of a carbonaceous lubricant, where the carbonaceous lubricant includes 2-4 volume % of coke relative to the total amount of the friction material composition, the average particle diameter of the coke is 300-800 m while the content of the inorganic friction modifier (a), (b), and the carbonaceous lubricant (c) satisfies the following formula: 1.0((a)+(b))/(c)2.5.

A constant velocity joint having a boot constructed from a thermoplastic polyether ester as the boot material. The boot includes a lubricating grease composition for lubricating the constant velocity joint, the lubricating grease composition comprising calcium lignin sulfonate.

A friction material composition including a fiber base material, a friction modifier and a binder. A content of copper in the friction material composition is 0.5% by mass or less. The friction material composition includes a partially graphitized coke and muscovite. A friction material is formed by molding the friction material composition.