Abstract: A thermally self-regulating elastomeric composition and heating element made therefrom. The composition includes a body of elastomeric material in which is distributed electrically conductive particulate material, such as carbon black. Short fibers are also distributed in the elastomeric matrix. In the disclosed invention, the short fibers are present in the amount of approximately 0.5 to 20 volume percent. In one alternate form, the matrix is foamed. Different arrangements of the electrodes in electrical conductive association with the thermally self-regulating elastomeric body are disclosed. Preferred proportions and characteristics of the particulate conductive material and short fibers providing optimum thermally self-regulating characteristics of the composition are disclosed.

Abstract: A pressure-responsive variable electrical resistive rubber material including at least one inorganic filler selected from a group consisting of conductive carbon black, short fibers of nonmetallic inorganic material, powder, and whiskers. The filler is dispersed in a matrix formed of an electrically insulative rubber. The rubber material exhibits a gradually reducing resistance value as a gradually increased pressing force is applied thereto. The rubber material provides a wide range of relationship between the applied force and the electrical resistance thereof. The rubber material is adapted for use as a pressure sensor having excellent fatigue creep resistance.