JPH03225709A - Formation of electrode layers of flexible piezoelectric body - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for forming electrode layers in a flexible piezoelectric body in which electrode layers are provided on the upper and lower surfaces. [Prior art] Piezoelectric organic substances such as polyvinylidene fluoride, polyvinyl fluoride, polyvinylidene chloride, polyvinyl chloride, and nylon, or strong organic substances such as lead zirconate titanate and lead titanate in the organic substances of synthetic rubber and synthetic resin. A flexible piezoelectric sheet such as a piezoelectric organic ceramic composite made of a mixture of dielectric ceramic particles has an acoustic impedance close to that of water. Therefore, electrode layers are formed on the front and back surfaces to form a flexible piezoelectric body, which is used as a piezoelectric transducer that receives acoustic waves propagating in water.

The flexible piezoelectric body is also used as a transmitter that emits sound waves or ultrasonic waves toward an object to be detected. Furthermore, the flexible piezoelectric material is a mechanical device that converts mechanical stress into electricity.
It is also used as an electrical conversion element.

In this way, flexible piezoelectric bodies have various uses.

[Problems to be Solved by the Invention] Conventionally, the electrode layer of a flexible piezoelectric material is formed by spreading and applying silver base to the front and back surfaces of a vulcanized flexible piezoelectric sheet. This was done by doing this.

However, for mass processing, it is necessary to overlap piezoelectric sheets with electrode layers formed on the front and back surfaces and transport them to the vulcanizer for the next process, and this overlapping can cause the silver paste to stick to each other or peel off. As a result, the silver paste layer, which has been spread and formed, breaks down and must be re-formed, making handling extremely troublesome.

A particularly big problem in manufacturing is that the process of forming the electrode layer, which is a relatively cottage industry-like job, and the vulcanization process, which requires a vulcanizer, are carried out in completely different places. After primary vulcanization, it is necessary to transport the piezoelectric sheet to another location, apply an electrode layer, and then transport it again to the vulcanizer for secondary vulcanization, which requires process control. It was troublesome and the workability was poor.

The present invention aims to eliminate the drawbacks of such conventional methods.

[Means for Solving the Problems] The present invention provides a carrier by applying a conductive coating layer made of silver, synthetic rubber, etc. dispersed in a solvent to a transfer plate having good high-temperature releasability. The carrier is applied to the front and back surfaces of the formed and post-vulcanized flexible piezoelectric sheet from the conductive paint layer side, second vulcanization is performed in the adhered state, and then the transfer plate is removed, This is a method for forming an electrode layer of a flexible piezoelectric material, characterized in that a conductive paint layer is transferred to the front and back surfaces of the piezoelectric sheet to form an electrode layer.

Here, as a transfer plate having good high-temperature releasability, a material obtained by impregnating an inorganic cloth such as glass cloth or ceramic cloth with a fluororesin and baking it at a high temperature may be used. The inorganic cloth is plain woven or special woven glass fiber or ceramic fiber, and the transfer plate made by impregnating this inorganic cloth with fluororesin and baking it at high temperature is suitable for various materials due to the characteristics of the fluororesin. , difficult to adhere;
In addition to good mold releasability, it has high chemical resistance and is not dissolved in organic solvents.

A conductive paint layer made of silver, synthetic rubber, etc. is applied onto such a transfer plate with good high-temperature releasability to form a carrier. Then, this carrier is applied to the front and back surfaces of the primarily vulcanized piezoelectric sheet, followed by secondary vulcanization to solidify the conductive paint layer and form an electrode layer that is bonded to the piezoelectric sheet side. After this, the transfer plate is peeled off.

[Example] A method for forming an electrode layer according to the present invention will be explained with reference to FIG.

In Figure 1A, l is a transfer plate, which is made by impregnating a glass cloth made of plain or special weave glass fibers with a fluororesin such as Teflon and baking it at high temperature. I am using it.

This thickness is 0.05 to 1. It is about oOm-. This product has excellent chemical resistance due to the fluororesin, and also has the characteristics of being difficult to adhere to various materials and having good mold releasability.

As shown in the opening in Figure 1, a conductive paint layer made by mixing and dispersing silver and synthetic rubber in toluene is applied to this transfer plate l in a spread form using a roll 4 or the like. Layer 2 is developed to form carrier 3 . This rolling promotes dispersion of the solvent. After this, a large number of carriers 3 are laminated and transferred to the location of the vulcanization process (see FIG. 1). At this time, each carrier 3 is laminated via the transfer plate l.
Due to the releasability of the transfer plate 1, they will not be bonded to each other,
Therefore, it is also possible to form and store a large amount of supporting bodies 3, which facilitates production control.

On the other hand, the piezoelectric sheet lO (Fig. 1 2) was heated to 10
Press vulcanization is performed by applying a pressure of about 0 to 200 kg/cm. After this vulcanization, a carrier 3 on which a conductive paint layer 2 is spread and formed on a transfer plate 1 is applied to the front and back surfaces of the piezoelectric sheet 10. , from the conductive paint layer 2 side (Fig. 1 E).This adhesion work does not require any liquid or complicated equipment, so the piezoelectric sheet lO is removed from the vulcanizer and immediately applied. Then, secondary vulcanization is performed by applying a pressure of about 50 to 150 Kg/c+e'' at high temperature in a vulcanizer. At this time, the coefficient of thermal expansion of the inorganic cloth constituting the transfer plate 1 is similar to that of the ceramic mixed in the piezoelectric sheet 10, and therefore, the conductive paint layer 2 is unlikely to be destroyed or cracked due to the difference in thermal expansion. Also, unlike ordinary fluororesin sheets that do not include inorganic cloth, it has great strength at high pressures and high temperatures.

After this vulcanization, the transfer plate 1 is peeled off from the front and back surfaces of the piezoelectric sheet IO (see FIG. 1). And at this time, the piezoelectric sheet lO
An electrode layer 11 formed by solidifying the conductive paint layer 2 is formed on the front and back surfaces of the electrode. In this peeling operation, only the transfer plate 1 can be easily peeled off because the transfer plate 1 has good releasability due to the characteristics of the fluororesin.

Thus, the flexible piezoelectric body 12 shown in FIG. 1G is formed.

"Effects of the Invention" As described above, the present invention covers the front and back surfaces of the piezoelectric sheet 10 with the carrier 3 formed by forming the conductive paint layer 2 on the transfer plate 1, and after vulcanizing this, the transfer plate Since the electrode layer 11 is formed on the front and back surfaces of the flexible piezoelectric body 12 by removing 1, the conductive paint layer 2 is spread in advance regardless of the manufacturing process of the piezoelectric sheet IO. production control is easy.

Even if a large number of carriers 3 are laminated in advance, the conductive paint layer 2 will not be transferred due to the transfer plate l having good mold releasability, making it possible to store and transport large quantities, and is suitable for large-scale processing.

C) Even if the surface of the conductive paint layer 2 at the top of the transfer plate l laminated as described above becomes dirty, the conductive paint layer 2 is reversed and deposited on the piezoelectric sheet 10, so that the surface is not exposed. Since it is a surface, the appearance of the piezoelectric body is not impaired.

−) When performing secondary vulcanization using a press, conventionally the conductive paint layer was directly pressurized, which resulted in peeling and abrasion of the fluororesin layer formed on the pressurized surface of the press, resulting in the electrode becoming smooth. It could be damaged. However, in the present invention, since pressure is applied via the transfer plate, there is no such problem.

f) The carrier 3 is formed in advance and the piezoelectric sheet 10 is
After the piezoelectric sheet 10 is primarily cured and taken out from the vulcanizer, the carrier 3 can be applied to the front and back surfaces of the piezoelectric sheet 10, and the second vulcanization can be carried out immediately, resulting in good workability.

f) Since pressure is applied while protecting the conductive paint layer 2 with the transfer plate 1 during secondary vulcanization, there is no damage to the electrode layer 11 during vulcanization.

[Brief explanation of drawings]

FIG. 1 is a manufacturing process diagram of an embodiment of the present invention. ■・・・Transfer plate 2... Conductive paint layer 3...Support 10...piezoelectric 11--Electrode layer to

Claims (1)

[Claims] A carrier is formed by applying a conductive paint layer made of silver, synthetic rubber, etc. dispersed in a solvent to a transfer plate with good high-temperature releasability, and then primary vulcanization. The carrier is applied to the front and back surfaces of a flexible piezoelectric sheet from the conductive paint layer side, and secondary vulcanization is performed in the adhered state, after which the transfer plate is removed and the conductive paint layer is applied to the front and back surfaces of the piezoelectric sheet. 1. A method for forming an electrode layer of a flexible piezoelectric material, the method comprising transferring the electrode layer to the back surface and using this as an electrode layer.