Abstract: A railroad brake shoe may include a friction element made by combining a number of materials so as to produce the required frictional characteristics for railroad braking. Heretofore, such friction elements commonly contained materials such as lead and asbestos. These two elements may have toxic characteristics under certain circumstances and therefore are suspect. To safely handle these suspect materials has thus become most difficult and expensive. By this invention, a composition friction element, which meets the requirements of the railroad industry, includes a substantially reduced suspect material content, yet is competitive in performance and cost with other known products.

Abstract: A composite friction element suitable for the manufacture of railroad brake shoes of the composition type is prepared from a mixture of a curable rubber binder having distributed therethrough a plurality of fillers and a reinforcing fiber, at least one of the fillers having an oil absorption value of at least 30 and the fiber being formed from an aramid polymer.

Abstract: Composition friction materials particularly adapted for use in making railroad brake shoes include an elastomer such as synthetic rubber or natural rubber. The elastomer forms part of a bond for the remaining friction ingredients. The elastomer, solvent and nonsolvent absorbing granular abrasive materials of the composition are mixed in a manner such that the elastomer is quickly reduced to a paste-like consistency to which the remaining ingredients are added and mixed to form pellets which can be conveniently formed into brake shoes.

Abstract: A friction material composition comprising asbestos fibers, mineral fillers which are heat stable, friction modifiers such as metal particles, abrasives, elastomer and ground polymerized and cured cashew nut shell oil wherein compositions are added which will favor the deposition of carbon at elevated temperatures and reduce the amount of intermediate decomposition products such as may cause fade. The invention is such as to permit the use of higher bond ratios and consequently produce better wearing, quieter friction materials which are more constant in action and kinder to the drum or disc against which they operate, maintaining a desirable high static friction when cold without an attendant fade condition when used under high energy conditions.