JPS61295678A - Manufacture of piezoelectric film - Google Patents

Abstract

PURPOSE:To facilitate the molding manufacture of a piezoelectric film and to make it a product being excellent in heat resistance and durability by a method wherein a calendering assistant is compounded in the mixture of dielec tric fine powder and polytetrafluoroethylene and a material thus prepared is molded into a film and then subjected to polarization. CONSTITUTION:Polytetrafluoroethylene (PTFE) is mixed in dielectric fine powder showing piezoelectric, pyroelectric or other electric characteristics, such as lead zirconia titanate (PZT), a calendering assistant is compounded in the mixture, and a material thus prepared is subjected to extrusion molding and then to calendering to be formd into a film of prescribed thickness. Then, it is subjected to polarization and thus a product is completed. Said film prepared by calendering is subjected to orientation to be formed into a porous film construction in which innumerable fine fibers are formed and connected in the shape of a spider web among minite knotting portions, and the gaps of holes of this porous film are impregnated with silicon rubber. Thereafter the film is subjected to polarization and thus a product is completed. As for the aforesaid dielectric fine powder, a mixture of barium titanate, lead titanate and lead zirconate or the like can be adopted in addition to PZT.

Description

Detailed Description of the Invention ``Object of the Invention'' The present invention relates to a method for manufacturing a piezoelectric film, which facilitates the molding and production of piezoelectric films used in electronic parts, speaker parts, etc., and improves heat resistance and durability. The aim is to provide a method that can provide products soaked in

BACKGROUND OF THE INVENTION As a piezoelectric film used in electronic components, a film using polyvinylidene fluoride is conventionally known.

Problems to be Solved by the Invention However, with the above-mentioned more conventional products, it is not necessarily easy to mold and manufacture them, and therefore they are expensive and have sufficient piezoelectric properties, as well as poor durability, heat resistance, and mechanical properties. There are disadvantages, such as the fact that the optical strength cannot be achieved, which is desirable. Furthermore, it has the disadvantage that the generated voltage is considerably lower than that of conventional ceramic-based ones.

"Structure of the Invention" Means for Solving the Problems Piezoelectricity characterized by mixing dielectric fine powder with polytetrafluoroethylene, adding a rolling aid, forming it into a film, and then subjecting it to polarization treatment. Film manufacturing method.

By adding a rolling aid to polytetrafluoroethylene mixed with working dielectric fine powder and extrusion rolling, it can be easily and precisely formed into a film.

The film is highly flexible and flexible, and since polytetrafluoroethylene is used, it has better heat resistance than conventional general plastic piezoelectric materials, and can generate a relatively large voltage.

As mentioned above, since it has good heat resistance, polarization treatment can be easily carried out by a conventional method.

EXAMPLE To further explain the fifth aspect of the present invention described above, polytetrafluorocarbon is added to a dielectric fine powder exhibiting electrical properties such as piezoelectricity and pyroelectricity, such as lead zirconate titanate (hereinafter referred to as PZT). Ethylene (hereinafter referred to as PTFE5)
A rolling aid is added to a mixture of A porous film structure is formed in which countless fine fibers are formed and connected in a spider's web shape, and the pores of the porous film are impregnated with silicone rubber, and then polarized in the same manner as above to produce a product. .

In addition to PZTO, barium titanate, a mixture of lead titanate and lead zirconate, etc. can be used as the dielectric fine powder described above, and the blending amount thereof is 50 to 98% by weight, preferably 80 to 98%, based on PTFKK. It is 95chi.

As the rolling aid to be added to the above mixture, solvent-based agents such as heptalic acid esters such as dibutyl phthalate and ingropanol are used, and the viscosity thereof is 5 to 5 at 30°C.
00 op- is preferable.

When silicone rubber is impregnated into the porous structure obtained by rolling it into a film, stretching it as necessary and removing the rolling aid, the porosity of the porous structure is about 3 to 30 cm. The amount of silicone rubber impregnated into the pores is appropriately selected within the range of 3 to 15 ts, taking into consideration the electrical characteristics of the intended product.

The polarization treatment is achieved by forming electrode portions such as vapor deposited layers on both sides of the film material, and applying a predetermined voltage using these as electrodes for a predetermined period of time at a predetermined temperature condition.

A specific manufacturing example of the product according to the present invention will be described below.

Production example 1゜Lead zirconate 31% PZT 100 vrt
After adding 50 vt parts of water to the mixture, the mixture was stirred for 30 minutes using a stirrer, and then a PTFI emulsion was mixed in at a ratio of 19 wt parts in terms of solid content, and the resulting mixture was coagulated and precipitated, and the resulting mixture was dried and ground. A mixed powder of PZT and PTF'E was prepared.

Dibutyl phthalate 85 is added to the above mixed powder as a rolling aid.
Add 14 wt parts of a liquid mixture of 15% and 15% isopropanol, mix in a blender, extrude into a round bar shape with a diameter of 30m and a length of 300mm at a pressure of 4mm, and then Repeat rolling to achieve width Zo
om.

It was molded into a film having a thickness of 0.1 m and a specific gravity of 5.0.

The film was cut into square pieces of 20 m x 20 cm, and aluminum 2 was vapor-deposited on both sides of the film 1 containing dielectric fine powder 3 to form electrodes as shown in FIG.
A product was obtained by polarization treatment by applying a voltage of ooov for 1.5 hours.

Production example 2゜ Width 10011II+ obtained in Production Example 1.

A film having a thickness of 0.1 m was stretched to 10 inches in the longitudinal direction, and the pores of a porous sheet obtained were impregnated with 5 inches of silicone rubber.

Film 1 impregnated with silicone rubber 4 as described above
For &, an aluminum evaporated film 2 was formed on the front and back sides as shown in FIG. As shown in the table below.

That is, it can be said that all of the devices according to the present invention are inferior to the conventional devices in terms of mechanical strength, etc., and are also inferior in piezoelectric properties.

"Effects of the Invention" According to the present invention as explained above, a piezoelectric film can be manufactured simply and accurately, and a product with uniform mechanical and electrical properties and an award-winning product can be obtained at a low cost. This is an invention with great industrial effects.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention, and FIG. 1 is an enlarged cross-sectional view showing the structure of one embodiment of the present invention, and FIG. 2 is FIG. 1 showing another embodiment thereof. It is an enlarged sectional view similar to. Therefore, in these drawings, 1.1a is a film, 2
Reference numeral 1 indicates an aluminum vapor deposited film, 3 indicates a fine powder of a deconductor, and 4 indicates a silicone rubber. 2nd circle

Claims (1)

[Claims] 1. A method for producing a piezoelectric film, which comprises mixing dielectric fine powder with polytetrafluoroethylene, adding a rolling aid, forming the film into a film, and subjecting the film to polarization treatment. 2. The method for producing a piezoelectric film according to claim 1, which comprises impregnating a porous structure formed into a film with silicone rubber.