초록 ▼

In order to increase the stability of a device comprising at least one electrode and a conductive polymer composition in contact therewith, the contact resistance between the electrode and the composition should be reduced. This can be achieved by contacting the molten polymer composition with the e

In order to increase the stability of a device comprising at least one electrode and a conductive polymer composition in contact therewith, the contact resistance between the electrode and the composition should be reduced. This can be achieved by contacting the molten polymer composition with the electrode while the electrode is at a temperature above the melting point of the composition. Preferably, the polymer composition is melt-extruded over the electrode or electrodes, as for example when extruding the composition over a pair of pre-heated wires.

대표청구항 ▼

An electrical device which has improved resistance stability under service conditions, which comprises two elongate electrodes, each of said electrodes being surrounded by and being in direct physical and electrical contact with a melt-extruded, electrically conductive polymer composition which (a)

An electrical device which has improved resistance stability under service conditions, which comprises two elongate electrodes, each of said electrodes being surrounded by and being in direct physical and electrical contact with a melt-extruded, electrically conductive polymer composition which (a) has a resistivity at 70°F. of less than 50,000 ohm.cm, and (b) comprises an organic polymer having dispersed therein a finely divided conductive filler, and in which device, when said electrodes are connected to a source of electrical power, current passes between the electrodes through the conductive polymer composition; wherein each of said electrodes has been surrounded and contacted by the conductive polymer composition by a process which comprises (1) heating a thermoplastic electrically conductive polymer composition to a temperature above its melting point, said composition comprising an organic polymer having dispersed therein a finely divided conductive filler; (2) heating each electrode, in the absence of the conductive polymer composition, to a temperature above the melting point of the conductive polymer composition; and (3) melt-extruding the molten conductive polymer composition prepared in step (1) over and into direct physical and electrical contact with the electrodes which have been heated in step (2), while each of the electrodes is at a temperature above the melting point of the conductive polymer composition, thereby forming an elongate extrudate of the electrically conductive composition with the electrodes embedded therein and in direct physical contact with the conductive polymer composition; said conductive polymer composition being such that if steps (1), (2) and (3) are carried out, and the extrudate is allowed to cool without taking any measures to reduce the resistivity of the extruded composition, the cooled composition has a resistivity at 70°F. of less than 50,000 ohm.cm; whereby the contact resistance between the electrodes and the conductive polymer composition in contact therewith is reduced.