Brake linings formulations

Manufacture of friction elements includes the impregnation of fabrics and subsequent lamination, the wet-dough process, and the dry-mix process. Elements from the last two are prepared by compression-molding the formulation for up to an hour at 150—175°C. Thick brake elements require a carefully controUed heating-and-cooHng cycle to minimize stresses created by expansion and contraction (see Brake linings and clutch facings Fillers). 

For example, brake linings contain finely divided, hard, abrasion resistant particles (Tab. 11-1, Chapter 11) in a complex matrix that provides the bonding in the lining itself and with the metallic supports. The formulation, containing all components, may also include such materials as metallic, mineral and, synthetic fibers. During production of the break drums, discs, or shoes, the blend is pressed onto the structural supports with specially designed presses to produce uniform, homogeneous wear pads. 

They dominate the field of wood adhesives and represent one of the largest volumes of any synthetic adhesive. Phenolics are also among the lowest-cost adhesives and may be formulated as water dispersions, to allow penetration into the cell structure of wood which is important for the formation of permanent bonds. Beyond the wood and wood products area, unmodified phenolics are used mainly as primers, to prepare metal surfaces for bonding, and as binders, for such varied products as glass wool insulation mats, foundry sand, abrasive wheels, and brake lining composites. Phenolics are supplied either as one-component, heat-curable liquid solution, as powder, or as liquid solution to which catalysts must be added. The curing mechanisms are different for these two groups. "... 

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