초록 ▼

The invention relates to heating elements comprising conductive polymers which are capable of undergoing a change in dimension. The heating elements comprise a laminar member composed of a conductive polymer and two laminar electrodes connected directly or indirectly to opposite faces of the laminar

The invention relates to heating elements comprising conductive polymers which are capable of undergoing a change in dimension. The heating elements comprise a laminar member composed of a conductive polymer and two laminar electrodes connected directly or indirectly to opposite faces of the laminar member, and there are apertures, for example slits, passing through the thickness of the element so that at least one planar dimension of the element can be changed by changing the shape of the apertures. The apertures through the element facilitate its dimensional change. Preferably the laminar member exhibits PTC characteristics. The heating elements are particularly useful in the form of articles in which the element is attached to a heat-responsive sheet, for example a heat-recoverable polymeric film.

대표청구항 ▼

A heating element which comprises: (A) a laminar member composed of a material which comprises an organic polymer and electrically conductive particles dispersed in the polymer in amount sufficient to render the member electrically conductive; and (B) a pair of laminar flexible electrodes which (i)

A heating element which comprises: (A) a laminar member composed of a material which comprises an organic polymer and electrically conductive particles dispersed in the polymer in amount sufficient to render the member electrically conductive; and (B) a pair of laminar flexible electrodes which (i) are connected to opposite faces of said laminar member; (ii) are substantially coplanar with said laminar member; and (iii) are adapted to be connected to an external source of power to cause current to pass through said laminar member; said laminar member and laminar electrodes having a plurality of apertures through the thickness thereof, the apertures being in parallel rows and being of elongated closed cross-section and overlapping one another to permit at least one of the dimensions of the element in the plane thereof to be changed by a change in the shape of the apertures.