Friction materials (US Patent 4,072,650, 1978)

John B. Littlefield received US Patent No. 4,072,650 on February 7, 1978, filed July 11, 1975.

The patent's 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. Specifically, dehydrogenation catalysts of an organic metallic base are added at least to the binder and in certain instances to the organic fillers to promote carbonization or coking at the working surface, without formation of intermediate molecular size compounds which contribute to fade conditions. The most satisfactory catalyst has been found to be ferrocene, otherwise known as dicyclopentadienyliron.

Where it was listed

• Asbestos, May 1978, in its patents department (the year's issues)