Process for recovering heat recoverable sheet material

Claim 1

A process for preparing an article which comprises: (1) connecting an external source of electric power to a pair of electrodes of an article which comprises a heat-recoverable sheet material and adjacent and secured to one face of the sheet material 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 in a plane substantially parallel with said laminar member; and (iii) are connected to said 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 aperturs being of elongated closed cross-section and overlapping one another to permit at least one of the dimensions of the heating element in the plane thereof to be changed by a change in the shape of the apertures; (2) passing current through said heating element until said sheet has been heated to a temperature at which it becomes responsive; thereby causing a change in the dimensions of said heating element and said sheet material at said temperature.