| 摘要 |
A process for making piezo-electric polyvinylidene fluoride (PVDF) film for use, for example, as diaphragms for telephone transmitters, includes the steps of: (a) stretching the melt-extruded film parallel to the extrusion direction with a stretch ratio of about 4 to 1 at about 120 DEG C. to convert it to a beta crystalline form; (b) clamping the film between conductive rubber pads to which the polarizing voltage, e.g. 1.3 kv for 12 mu m film is applied. While the voltage is thus applied, the film is heated to about 110 DEG C. for 130 mins. and cooled to ambient with the polarizing filed preset; (c) conductive elastomer electrodes are applied to the film in the desired pattern; and (d) the piezo-electric properties are stabilized by heating the foil to about 90 DEG C. for 2 hours. |
