JPS63111685A - Manufacture of composite piezoelectric material - Google Patents

Abstract

PURPOSE:To manufacture a composite piezoelectric material with reduced loss of the material and labor by a method wherein plate-shaped bodies of an inorganic piezoelectric substance, each of which has a cut in a prescribed width, are bonded on a substrate in parallel juxtaposition with prescribed intervals between them, the substrate thus prepared is put in a molding die, a setting synthetic resin solution is filled up and set in the molding die, and thereafter the substrate, the continuous part of the inorganic piezoelectric substance bonded to the substrate and a peripheral synthetic resin part are cut for removal. CONSTITUTION:Plate-shaped bodies 4 of an inorganic piezoelectric substance polarized in the direction of the width of a rectangle are bonded in parallel juxtaposition with prescribed intervals between them on a synthetic resin substrate 3 set on a bottom plate 6 of a molding die. Then, a side wall frame 5 of the molding die is put on, a setting synthetic resin solution is poured and filled up therein, and a molded body is taken out of the molding die after setting and/is given cuts in prescribed numbers at prescribed in the direction of a line A-A. The molded body given the cuts is put again in the molding die so as to fill up and set the same setting synthetic resin solution as the above in the cut parts. Thereafter said body is taken out of the molding die, the substrate 3 in the lower part of the body and the peripheral part of the synthetic resin are cut to be removed, and thus a composite piezoelectric material is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a composite piezoelectric material of an inorganic piezoelectric material and an organic material, and more specifically, the electromechanical coupling coefficient, which is a measure of the conversion efficiency of electricity and external force and the pressure sensitivity. The present invention relates to a method for easily and efficiently manufacturing a composite piezoelectric material having a large pressure SS pressure constant.

The composite piezoelectric material of the present invention is suitable for use as a piezoelectric element that utilizes the piezoelectric effect, particularly as an ultrasonic wave receiver and a pressure-sensitive sensor.

[Technical background and explanation of conventional technology]

Inorganic ceramic piezoelectric materials such as barium titanate or PZT (lead zirconate titanate Pb (Zr, Ti) O) have a large electromechanical coupling coefficient, but the piezoelectric voltage constant is lower than that of organic polymer piezoelectric materials. small.

Furthermore, even though organic polymer piezoelectric materials have piezoelectricity, they have a small electromechanical coupling coefficient.

For piezoelectric materials that utilize the piezoelectric effect, that is, ultrasonic receiving elements or pressure-sensitive sensors, piezoelectric materials that are soft and have a large electromechanical coupling coefficient and piezoelectric voltage constant are desired, and piezoelectric materials such as barium titanate and PZT are desired. Attempts have been made to manufacture piezoelectric materials with large electromechanical coupling coefficients and piezoelectric voltage constants by combining inorganic ceramic piezoelectric materials and polymeric organic materials. In the United States, Newham et al.
We create ZT fibers, combine them with organic matter, and perform polarization treatment. [Journal of the
American Ceramic Society (Journa)
l of the American Ceramie
5ociety) Vol. 64, No. 1, pp. 5-8] However, in this method, it is difficult to uniformly apply a high voltage to the composite material because the electrical properties of PZT and the organic material are different. Therefore, Takeuchi et al. produced a composite piezoelectric material with a similar structure (]-3-3 connections) by cutting a thin plate of PZT that had been subjected to polarization treatment. (Japanese Unexamined Patent Application Publication No. 58-21.883) However, in the 1-3 bond structure, as the volume fraction of ceramics increases, the overall hardness increases, and high piezoelectricity cannot be obtained due to the clamping effect. Although it is necessary to reduce the volume fraction, according to the method of Takeuchi et al., 50 to 80% of the volume of the ceramic material must be discarded by cutting.
This increases the manufacturing cost of the composite piezoelectric material.

The present inventor has conducted extensive research with the aim of manufacturing a composite piezoelectric material of an inorganic piezoelectric material with a small volume fraction and an organic material with less loss of material, and has developed a composite piezoelectric material made of an inorganic piezoelectric material with a small volume fraction and an organic material. It has been discovered that if the materials are spaced apart and bonded in parallel, the loss of material corresponding to the predetermined distance can be prevented, and based on this knowledge, the present invention has been achieved.

[Object of the invention and summary of the invention]

An object of the present invention is to provide a method for manufacturing a composite piezoelectric material of an inorganic piezoelectric material and an organic material with a small volume fraction while reducing material loss. It is an object of the present invention to provide a method for manufacturing a composite pressure 'II august material with less loss of material and less labor.

The present invention comprises a substrate in which inorganic piezoelectric plate-like bodies with cuts of a predetermined width are arranged in parallel with a predetermined interval and bonded together.
The mold is filled with a curable synthetic resin liquid, and after it hardens, the substrate, the continuous portion of the inorganic piezoelectric material bonded to the substrate, and the surrounding synthetic resin portion are cut and removed to form a prismatic inorganic piezoelectric material. This is a method for producing a composite piezoelectric material, which is characterized by obtaining a composite piezoelectric material whose bodies are regularly arranged in a matrix of synthetic resin.

In the production of the composite piezoelectric material of the present invention, the notches made in the inorganic piezoelectric plate and the spacing when the inorganic piezoelectric materials are arranged parallel to the substrate and bonded are the synthetic resin in the composite piezoelectric material. In the composite piezoelectric material of the present invention, prismatic inorganic piezoelectric bodies are regularly arranged in a synthetic resin matrix.

The composite piezoelectric material of the present invention is manufactured by gluing inorganic piezoelectric plate plates arranged in parallel on a substrate at a predetermined interval.
The substrate is placed in a mold, the mold is filled with a curable synthetic resin liquid, the cured material is removed from the mold,
Cuts are made at predetermined intervals in a direction perpendicular to the direction in which the inorganic piezoelectric materials are lined up in parallel, and the molded product with these cuts is placed into the mold again and filled with the same curable synthetic resin liquid as above. This can be carried out by filling a mold with the material, curing it, taking out the molded body, and cutting and removing the substrate, the continuous portion of the inorganic piezoelectric material adhered to the substrate, and the surrounding synthetic resin portion.

Furthermore, in order to manufacture the hybrid piezoelectric material of the present invention, cuts are made at predetermined intervals in a plate-like inorganic piezoelectric material, and the plate-like inorganic piezoelectric material with the cuts is placed on a substrate. Leave a predetermined interval, arrange the substrates in parallel, and glue them together, put the substrates into a mold, fill the mold with a curable synthetic resin liquid, and after curing, take out the molded body, and insert the substrates and substrates in the same way as above. This can also be done by cutting and removing the continuous portion of the inorganic piezoelectric material and the surrounding synthetic resin portion adhered to the material.

In the production of the composite piezoelectric material of the present invention, when bonding inorganic piezoelectric plate-shaped bodies on a substrate in parallel with a predetermined interval, leave a predetermined interval on both side walls of the substrate. The inorganic piezoelectric material can be bonded to the substrate by placing an alignment mold that fills the guide grooves formed by the method, and fitting a plate-shaped inorganic piezoelectric material into the guide grooves. By using this alignment mold, the inorganic piezoelectric plate can be easily and accurately bonded to the substrate.

In the production of the composite piezoelectric material of the present invention, the inorganic piezoelectric plate can be polarized in the direction perpendicular to the surface bonded to the substrate. Barium titanate can be used as the inorganic piezoelectric material, and curable synthesis wl! Epoxy horse chestnut resin can be used as the synthetic resin in the fat solution, and an epoxy resin plate can be used as the substrate to which the inorganic piezoelectric plate-shaped body is bonded.

[Detailed description of the invention]

As shown in FIG. 4, the composite piezoelectric material of the present invention has a large number of prismatic inorganic piezoelectric bodies 1 regularly arranged in a matrix 2 of a cured synthetic resin.

In manufacturing the composite piezoelectric material according to the present invention, a plate-shaped body of an inorganic piezoelectric material is prepared as a material. This plate-like inorganic piezoelectric material is rectangular and needs to be polarized by applying a DC voltage in the direction of the rectangular part, and its thickness is set regularly within the synthetic resin matrix 2. It is necessary that the length of one side of the arrayed prismatic inorganic piezoelectric bodies l be equal to the length of one side, and furthermore, the direction of the polarization treatment of the plate-like bodies of the inorganic piezoelectric bodies must be regularly set in the matrix 2 of the synthetic resin of the composite piezoelectric material of the product. It is necessary to match the height direction of the arranged prismatic inorganic piezoelectric bodies.

A rectangular inorganic piezoelectric plate polarized in the width direction 4
As shown in FIGS. 1 and 2, the bottom plate 6 of the mold is
They are adhered to the synthetic resin substrate 3 placed on the substrate 3, arranged in parallel with a predetermined interval. A side wall frame 5 of the mold is fitted into this to form a mold, and a curable synthetic resin liquid is poured into the mold and filled, and plate-shaped inorganic piezoelectric materials are arranged in parallel and bonded to the substrate 3. 4 and the space between the inorganic piezoelectric plate 4 and the side wall formwork 5 of the mold are all filled with a curable synthetic resin liquid. After filling, the curable synthetic resin liquid is cured, and after curing, the molded body is taken out from the mold. This molded body is placed in a holder of a precision cutting machine, and the molded body is placed in a direction perpendicular to the length direction of the inorganic piezoelectric plate-like bodies 4 arranged in parallel in the molded body, that is, a second A predetermined number of cuts are made at predetermined intervals in the direction of line A-A in the figure. By forming this notch,
The inorganic piezoelectric plate 4 is separated into a prismatic shape,
Its lower part is bonded to the substrate 3, and its two opposing sides are fixed with hardened synthetic resin, so the arrangement of the prismatic inorganic piezoelectric bodies remains unchanged.

The molded body with this incision is put into the mold again, and the cut area is filled with the same curable synthetic resin liquid as above, and after curing, the molded body is taken out of the mold, as shown in Figure 3. A molded body of a composite piezoelectric material in which prismatic inorganic piezoelectric bodies are regularly arranged in a synthetic resin matrix 2 as shown in the plan view is obtained.

This molded body is taken out from the mold again, and the lower substrate 3 and the surrounding synthetic resin portion are cut and removed.
A composite piezoelectric material of the present invention is obtained in which prismatic inorganic piezoelectric bodies are regularly arranged in a synthetic resin matrix 2 as shown in the figure.

In manufacturing the composite piezoelectric material of the present invention, when making cuts in the molded body in which the inorganic piezoelectric plate bodies 4 are arranged parallel to each other in the synthetic resin matrix 2, the depth of the cuts is set to the substrate. 3, and leave the inorganic piezoelectric plate-shaped body 4.
A continuous portion 41 is left at the bonded portion with the substrate 3, and each of the inorganic piezoelectric plate-like bodies 4 has a shape consisting of the continuous portion 41 and the prismatic portion 11 as shown in FIG. Can be done. In this case, the synthetic resin matrix 2
When cutting and removing the substrate 3 at the bottom of the molded body in which the prismatic inorganic piezoelectric materials l are regularly arranged, if the continuous portion 41 of the inorganic piezoelectric material adhered to the substrate 3 is cut and removed together with the substrate 3, as shown in FIG. The composite piezoelectric material of the present invention in which prismatic inorganic piezoelectric bodies 1 are regularly arranged in a synthetic resin matrix 2 can be manufactured as shown in FIG.

The composite piezoelectric material of the present invention can be produced by the following method in which a prismatic inorganic piezoelectric material is formed in advance by making cuts in a plate-like inorganic piezoelectric material, and the prismatic inorganic piezoelectric material is not formed in a mold. It can be manufactured by

In this method, a plate-shaped body of an inorganic piezoelectric material is fixed to a holder of a precision cutting machine, cuts are made at predetermined intervals on the side surface of the plate-shaped body, and a continuous portion 41 and a prismatic portion are formed as shown in FIG. A comb-shaped inorganic piezoelectric body consisting of 11 pieces is manufactured. The comb-shaped inorganic piezoelectric material 4 is adhered to a synthetic resin substrate 3 placed on a bottom plate 6 of a mold as shown in FIG. 1, in parallel rows at a predetermined distance. The side wall form 5 of the mold is fitted into this, and the mold is filled with a curable synthetic resin liquid. After curing, the molded body is taken out from the mold, and the prismatic inorganic piezoelectric body l is made of synthetic resin. A molded body regularly arranged in a matrix 2 is manufactured.

The upper part of this molded body has prismatic inorganic piezoelectric bodies 1 regularly arranged in a synthetic resin matrix 2, as shown in FIG. A prismatic inorganic piezoelectric material 1 is formed by a continuous portion of the inorganic piezoelectric material.
are connected. The substrate 3 at the bottom of this molded body and the continuous portion of the inorganic piezoelectric material bonded thereon are cut and removed together, and the surrounding composite m-finger portion is further cut and removed.
A composite piezoelectric material of the present invention is obtained in which prismatic inorganic piezoelectric bodies 1 are regularly arranged in a synthetic resin matrix 2 as shown in the figure.

In the production of the composite piezoelectric material of the present invention, when inorganic piezoelectric plate bodies 4 or comb-shaped inorganic piezoelectric bodies 4 are arranged and adhered in parallel with a predetermined interval on a synthetic resin substrate 3, Guide grooves 8.8 on the inside of both side walls as shown in FIG.
8.8,... is placed, and inorganic piezoelectric plate plates 4.4, 4... are fitted into the guide grooves 8.8 of the inorganic piezoelectric plate plates 7. The bodies 4.4, . . . can be bonded to the synthetic resin substrate 3.

By using this alignment formwork 7, the inorganic piezoelectric plate 4
Alternatively, the synthetic resin of the inorganic piezoelectric material (2) can be easily and accurately arranged on the substrate 3.

Barium titanate, lead titanate, and lead zirconate titanate (PZT) can be used as the inorganic piezoelectric body in producing the composite piezoelectric material of the present invention, and the curable synthetic resin can be epoxy resin, urethane resin, silicone resin,
Thermosetting 1 such as polyester resin or phenolic resin
Thermoplastic resins such as acrylic resins, polystyrene resins, nylon resins, polyethylene resins or polypropylene resins can be used.

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 (Production of barium titanate plate-epoxy resin composite molded body) An epoxy resin substrate was placed on the bottom plate (diameter: 3 (1 m)) of a polyethylene mold [30 mm (inner diameter) x 30 III (depth)].
30 mm (diameter) x 5 mm (thickness)], and on top of this a barium titanate piezoelectric plate (20 m) polarized in the width direction.
m (length) x 8 mm (width) x 1.5 mm (thickness)] with the width direction as the vertical direction, aligning the polarization direction, and leaving an interval of 300 pm, using an adhesive (product name: Nearon Alpha, Toa 10 sheets were glued together in parallel using a product from Synthetic Kagaku Co., Ltd.). A polyethylene type side wall formwork is fitted into this bottom plate to form a polyethylene mold, and then an epoxy resin [trade name: Ebicoat 807/Evomate B-0] is applied to this polyethylene mold.
Pour 02W (hardening agent), a product of Yuka Shell Co., Ltd.
The space between the barium titanate piezoelectric plates and the mold is filled with epoxy resin and cured, and 10 barium titanate piezoelectric plates are placed in the cured epoxy resin with a thickness of 300 μm.
A barium titanate plate-epoxy resin composite molded body embedded in parallel with an interval of m was manufactured.

(Production of barium titanate-epoxy resin composite piezoelectric body) Take out the barium titanate plate-epoxy resin composite molded body (30 fins (outer diameter) x 25 mm (height)) from the polyethylene mold and place it in the holder of a precision cutting machine. fixed to 300μ
Using a diamond blade with a thickness of m, 1.5+a+x
300μm wide grooves (depth: 8++I) with intervals of
Ten pieces were formed in the vertical direction perpendicular to the direction in which the barium titanate piezoelectric plates were arranged. This grooved barium titanate plate-epoxy resin composite molded body is placed again into the polyethylene mold, and the epoxy resin is poured into the grooves and cured, and the barium titanate piezoelectric body is placed inside the epoxy resin molded body. [1.5 mm (vertical) x 1.5 mm (
Horizontal) x 8 fins (length):] 100 fins are 30011r
A barium titanate-epoxy resin composite molded body was manufactured in which the molded barium titanate-epoxy resin was embedded in a regular, dense array at intervals of rL.

This barium titanate-epoxy resin composite molded body was taken out from the polyethylene mold, and the epoxy resin-only part at the periphery was cut and removed to form a barium titanate-epoxy resin composite piezoelectric body [18 mm (vertical) x + am (horizontal)]. X8
Tomo (height)] was produced.

This barium titanate-epoxy resin composite piezoelectric body has a prismatic barium titanate piezoelectric body [1,5111+(vertical)Xl,511jI(
Horizontal) x 8 (length) ) 100 pieces is 300py
They were regularly arranged at intervals of x, the volume fraction of barium titanate was 55%, and the overall density was 3.8719/c11.

(Measurement of electrical properties) Epoxy conductive resin (product name: Epoxy-338
0, a product of Three Bond Co., Ltd.) to form an electrode, and the specific inductivity (ε/ε) and electromechanical coupling coefficient kt (%
) and piezoelectric constant (F) were measured.

The results were as shown in Table 1.

Example 2 (Processing of barium titanate piezoelectric plate) Barium titanate piezoelectric plate subjected to polarization treatment in the width direction [
20 mm (length) x 8 mm (width) x 1.5 mm (thickness)] 5 sheets were tied together with their polarization directions aligned, and the bundle was fixed in the holder of a precision cutting machine to a thickness of 300 μm. Using a diamond blade, cut 10 grooves (300 μm wide x 7 deep) at a pitch of 1.84 perpendicular to the length direction of the board and perpendicular to the direction in which the boards are lined up. After forming, the bundle was untied to produce a comb-shaped barium titanate piezoelectric plate in which 1.5+*m square prisms were arranged in a comb-blade shape.

(Production of barium titanate-epoxy resin composite piezoelectric body) An epoxy resin plate (diameter = 3
0), place a comb-shaped barium titanate piezoelectric plate on top of it, with the comb-shaped base part facing down, and use adhesive (trade name: Nialon Alpha, manufactured by Toagosei Kagaku Co., Ltd.). Five pieces were glued in parallel, with an interval of 2 mm. Add polyethylene side wall formwork to this [30III + (inner diameter)
0 questions (depth)], pour the epoxy resin [Product 8: Ebikoat 807/Evomate B-002W (hardening agent), Yuka Shell Co., Ltd. product] into it, fill the space, harden it, A barium titanate-epoxy resin composite molded body was manufactured.

This barium titanate-epoxy resin composite molded body was taken out of the polyethylene mold, and the 6-inch section was cut from the bottom of the body, and the base portion of the comb-shaped barium titanate piezoelectric body and the epoxy resin plate were cut and removed. Furthermore, the epoxy resin part around the periphery was cut and removed to form a barium titanate-epoxy resin composite piezoelectric body [18 mm (vertical) x 1
5.5 mm (horizontal) x 7 mm (thickness)].

This barium titanate-epoxy resin composite piezoelectric material has a square column of barium titanate piezoelectric material [1, 5 (vertical) x 1, 5 (horizontal) x 7 (height)] in an epoxy resin matrix. 55110 pieces 0.3mm (vertical) x 2m
The barium titanate piezoelectric materials were embedded in regular arrays with intervals of lI (horizontal), the volume fraction of the barium titanate piezoelectric material was 29%, and the overall density was 3.39 jJ/ca.

(Measurement of Electrical Properties) The electrical properties of this barium titanate-epoxy resin composite piezoelectric material were measured in the same manner as in Example 1.

The results were as shown in Table 1.

Table 1 Barium titanate-epoxy resin composite Example 3 On the epoxy resin plate placed on the polyethylene bottom plate, guide grooves with a width of 1.6 mm were formed on the left and right side walls of the 0.2 mm width. Place the alignment formwork formed at intervals, fit a barium titanate piezoelectric plate that has been polarized in the width direction into the guide groove, and use adhesive (same as in Example 1) to After bonding the barium titanate piezoelectric plate to the epoxy resin plate, the alignment mold was removed and the barium titanate piezoelectric plate was bonded in parallel onto the epoxy resin plate, but the same procedure as in Example 1 was carried out. Then, a barium titanate-epoxy resin composite piezoelectric body was manufactured.

This barium titanate-epoxy resin composite piezoelectric body was the same as that of Example 1.

〔Effect of the invention〕

In the present invention, a plate-like body of an inorganic piezoelectric material is placed on a substrate,
By gluing them parallel to each other at specified intervals,
In manufacturing the composite piezoelectric material of the present invention in which prismatic inorganic piezoelectric bodies are regularly arranged in a matrix of synthetic first frost, loss due to cutting of the inorganic piezoelectric body can be reduced.

Furthermore, labor can be saved by reducing the number of cutting steps.

In the production of the composite piezoelectric device of the present invention, when the inorganic piezoelectric plate-shaped bodies are arranged and bonded in parallel on the substrate at a predetermined interval, an aligned type with B4 grooves provided on the inside of both side walls is used. The use of the frame simplifies the operation of adhering the inorganic piezoelectric material onto the substrate, and also allows for accurate alignment.

[Brief explanation of the drawing]

FIG. 1 shows the manufacturing process of the composite piezoelectric material of the present invention.
FIG. 2 is a side view showing a state in which an inorganic piezoelectric plate-like body is adhered to a substrate, FIG. FIG. 3 is a plan view of a molded product in the manufacturing process of the composite piezoelectric material. FIG. 4 is a perspective view of a composite piezoelectric material manufactured according to the present invention;
FIG. 5 is a perspective view of an intermediate product in which a plate-like inorganic piezoelectric material is cut into a fence shape in the production of the composite piezoelectric material of the present invention, and FIG. It is a perspective view of the alignment formwork used in manufacturing. [Drawing code] 1: Prismatic inorganic piezoelectric material 2: Synthesis I! l fat matrix 3: synthetic resin substrate 4: inorganic piezoelectric plate 5: mold side wall form 6: mold bottom plate 7: alignment form 8: dielectric 4 grooves

Claims (6)

[Claims] (1) A substrate on which inorganic piezoelectric plate-shaped bodies with cuts of a predetermined width are lined up in parallel with a predetermined interval and glued is placed in a mold, and the mold is filled with a curable synthetic resin liquid. After curing, the substrate, the continuous portion of the inorganic piezoelectric material adhered to the substrate, and the surrounding synthetic resin portion are cut and removed to obtain a composite piezoelectric material in which prismatic inorganic piezoelectric materials are regularly arranged in a synthetic resin matrix. A method for producing a composite piezoelectric material characterized by: (2) A substrate in which plates of inorganic piezoelectric material with cuts of a predetermined width are glued to each other in parallel with a predetermined interval are placed on the substrate. Place this substrate in a mold, fill the mold with a curable synthetic resin liquid and harden it, take out the molded body from the mold, and form a plate-shaped inorganic piezoelectric material. Manufacturing the composite piezoelectric material according to claim 1, which is manufactured by making cuts at predetermined intervals in a direction perpendicular to the direction in which the bodies are arranged in parallel. Method. (3) Plates of inorganic piezoelectric material with cuts of a predetermined width are cut at predetermined intervals, and a substrate, which is lined up and bonded in parallel, is cut into the plate of inorganic piezoelectric material at predetermined intervals. Claim 1 is characterized in that the inorganic piezoelectric body is manufactured by attaching the inorganic piezoelectric body to the substrate and arranging the inorganic piezoelectric body in parallel with a predetermined interval on the substrate and gluing it. A method for manufacturing composite piezoelectric materials. (4) Inorganic piezoelectric plate-shaped bodies are arranged and bonded in parallel on a substrate at a predetermined interval, and guide grooves are formed on both side walls of the substrate at a predetermined interval. Claim 2 or 3, characterized in that the method is carried out by placing an alignment mold, fitting a plate-like inorganic piezoelectric material into the guide groove, and bonding the plate-like inorganic piezoelectric material to a substrate. A method for producing a composite piezoelectric material according to item 3. (5) According to any one of claims 1 to 4, wherein the inorganic piezoelectric plate is polarized in a direction perpendicular to the surface bonded to the substrate. A method of manufacturing the composite piezoelectric material described. (6) The inorganic piezoelectric plate is a barium titanate plate, the synthetic resin in the curable synthetic resin liquid is an epoxy resin, and the substrate is an epoxy resin substrate. A method for manufacturing a composite piezoelectric material according to any one of claims 1 to 5.