JP6198274B2 - Piezoelectric material collection method and reuse method - Google Patents

Description

  The present invention relates to a piezoelectric material recovery method for recovering a piezoelectric material from piezoelectric rubber, and a piezoelectric material reuse method for reusing the piezoelectric material recovered from the piezoelectric rubber.

  Piezoelectric materials are used in a wide variety of applications such as sensors and actuators. However, since it contains lead, there is a problem that disposal is difficult. In a conventional method for recovering a piezoelectric material (Prior Art 1), lead is recovered from a PZT sintered body using sulfuric acid with a wet ball mill (see, for example, Non-Patent Document 2). In this prior art 1, a coarse powder of PZT sintered body and sulfuric acid are enclosed together with alumina balls for grinding in a polypropylene (PP) pot, wet ball milling is performed at room temperature, and a white powder of lead sulfate single phase. Is recovered.

  In a conventional method for recovering a piezoelectric material (prior art 2), lead is recovered from lead zirconate (PZT) ceramics by a wet ball mill using an aqueous sulfuric acid solution (for example, see Non-Patent Document 1). In this prior art 2, lead is recovered from PZT ceramics with an aqueous sulfuric acid solution at a fixed rotation speed of 300 rpm for 96 hours at room temperature in air using a wet ball mill.

  A conventional method for recovering a piezoelectric material (Prior Art 3) is that an electronic device using a lead-containing piezoelectric material is put into an organic solvent, dried, exposed to a high-temperature atmosphere, put into an acid, and a piezoelectric material containing lead (See, for example, Patent Document 1). In this prior art 3, the exterior resin of the electronic device is dissolved with the second type organic solvent, an inorganic compound such as solder is exposed in a high temperature atmosphere of 300 to 800 ° C., and finally it is introduced into an acid such as nitric acid. The silver electrode is dissolved and the remaining lead-containing material is separated and recovered.

Ryo Sakurai et al., "Recovery of valuable and hazardous metals from ceramic waste", Journal of the Japan Society for Waste Management, Japan Society for Waste Resource Circulation, 2004, Vol.15, No.4, p.168-174

Takehiro Kamiya et al., “Recovery of lead from PZT ceramics by ball mill using acidic solvent”, Journal of the Ceramic Society of Japan, The Ceramic Society of Japan, November 1, 2003, 111 (1299), p.806 -810

Japanese Unexamined Patent Publication No. 2000-101161

  Prior art 1 is a separation and recovery method using heavy liquid, which separates lead from the coarse powder of the PZT sintered body using the difference in specific gravity. However, in the prior art 1, a heavy liquid with a high specific gravity is toxic and is difficult to dispose of, so it is not suitable for collecting PZT, and there is no heavy liquid with a high specific gravity that can collect PZT.

  Prior art 2 is a method for dissolving and recovering inorganic materials with acid and alkali, and separates lead from PZT ceramics by utilizing solubility. However, in the prior art 2, zircon and titanium are hardly soluble in acid and insoluble in alkali. Further, in the prior art 2, since zinc and lead are easily dissolved in acid and alkali, it is considered unsuitable for recovery of PZT and cannot be taken out as piezoelectric ceramics.

  In Prior Art 3, the exterior resin of the electronic device is dissolved by the second type organic solvent, and an inorganic compound such as solder is heated in an oxygen atmosphere. However, in the prior art 3, when the exterior of the electronic device is a crosslinked rubber, there is a problem that the crosslinked rubber is not dissolved in the second type organic solvent. Further, in the prior art 3, when the oxygen concentration is low, oxygen in the piezoelectric material is consumed for the combustion of rubber, the piezoelectric material becomes brittle, and the particles of the piezoelectric material are crushed and become small.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a method for recovering a piezoelectric material that can be easily separated and recovered from a piezoelectric rubber and reused, and a method for recycling the same.

The present invention solves the above-mentioned problems by the solving means described below.
In addition, although the code | symbol corresponding to embodiment of this invention is attached | subjected and demonstrated, it is not limited to this embodiment.
The invention of claim 1 is a method for recovering a piezoelectric material for recovering a piezoelectric material (1b) from a piezoelectric rubber (1) as shown in FIGS. 2 to 4, wherein the electrode portion (2A, 2B ) is recovered from the piezoelectric rubber. ) With an organic solvent (S), a cutting step (# 110) for cutting the piezoelectric rubber after the removing step, and heat for thermally decomposing the piezoelectric rubber after the cutting step This is a piezoelectric material recovery method (# 100) including a decomposition step (# 130) and a separation step (# 140) for separating the piezoelectric material from the decomposition residue (5) after the thermal decomposition step.

  According to a second aspect of the present invention, in the method for recovering a piezoelectric material according to the first aspect, the thermal decomposition step includes a step of thermally decomposing the organic compound by heating the piezoelectric rubber in the air. This is a method for collecting a piezoelectric material.

The invention of claim 3 is a piezoelectric material recovery method for recovering the piezoelectric material (1b) from the piezoelectric rubber (1) as shown in FIGS. 2 to 4, wherein the piezoelectric rubber is cut (# 110), a thermal decomposition step (# 130) for thermally decomposing the piezoelectric rubber after the cutting step, and a separation step (# 140) for separating the piezoelectric material from the decomposition residue (5) after the thermal decomposition step hints, the separation step, the particle size of the decomposition residue is method of recovering a piezoelectric material (# 100), characterized in that it comprises a step of recovering the decomposition residue as the piezoelectric material exceeds a predetermined value.

The invention of claim 4 is a method for reusing a piezoelectric material, wherein the piezoelectric material (1b) recovered from the piezoelectric rubber (1) is reused, as shown in FIGS. A kneading step (# 210) for kneading the piezoelectric material with the raw rubber material (1c), and a molding vulcanization step (# 220) for vulcanizing the kneaded product (b) after the kneading step to form the piezoelectric rubber. The kneading step includes a step of kneading the piezoelectric material collected by the piezoelectric material collecting method according to any one of claims 1 to 3 with a raw rubber material. This is a reuse method (# 200).

According to a fifth aspect of the present invention, in the method for reusing a piezoelectric material according to the fourth aspect , an electrode forming step (# 230) for forming electrode portions (2A, 2B) on the piezoelectric rubber after the molding vulcanization step is provided. A method for reusing a piezoelectric material characterized in that the piezoelectric material is included.

According to a sixth aspect of the present invention, there is provided the piezoelectric material recycling method according to the fourth or fifth aspect , further comprising a polarization processing step (# 240) for polarizing the piezoelectric rubber. How to use.

  According to this invention, the piezoelectric material can be easily recovered from the piezoelectric rubber and reused.

It is sectional drawing which shows typically the piezoelectric rubber collect | recovered and reproduced | regenerated by the collection method of the piezoelectric material which concerns on embodiment of this invention, and its reuse method. It is a conceptual diagram of the collection | recovery method of the piezoelectric material which concerns on embodiment of this invention, and its reuse method. It is process drawing of the collection method of the piezoelectric material which concerns on embodiment of this invention. It is a schematic diagram for demonstrating the collection method of the piezoelectric material which concerns on embodiment of this invention, (A) is a schematic diagram which shows the piezoelectric material before a removal process, (B) is a schematic diagram which shows a removal process. (C) is a schematic diagram showing a cutting step, (D) is a schematic diagram showing a thermal decomposition step, and (E) is a schematic diagram showing a separation step. It is process drawing of the reuse method of the piezoelectric material which concerns on embodiment of this invention. It is a schematic diagram for demonstrating the reuse method of the piezoelectric material which concerns on embodiment of this invention, (A) is a schematic diagram which shows a kneading | mixing process, (B) is a schematic diagram which shows a shaping | molding vulcanization | cure process. (C) is a schematic diagram which shows an electrode formation process, (D) is a schematic diagram which shows a polarization process process.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
A piezoelectric rubber 1 shown in FIG. 1 is a member in which a piezoelectric material is dispersed in rubber. The piezoelectric rubber 1 outputs an electrical signal according to a load acting on the piezoelectric rubber 1. The piezoelectric rubber 1 is a piezoelectric element having elasticity, converts vibration into an electric signal by a piezoelectric effect, and generates electric power according to the magnitude of vibration (magnitude of load). The piezoelectric rubber 1 includes a rubber material 1a and a piezoelectric material 1b. The piezoelectric rubber 1 is a plate-like member formed in a predetermined shape, for example, as shown in FIG.

  The rubber material 1a is a base material that holds the piezoelectric material 1b. The rubber material 1a is made of, for example, natural rubber, nitrile rubber, butadiene rubber, styrene butadiene rubber, butyl rubber, ethylene propylene rubber (EPDM), chloroprene rubber, fluorine rubber, silicone rubber, urethane rubber, polynorbornene rubber or acrylic rubber. Thermoplastic elastomer (TPE) such as vulcanized rubber, styrene, olefin, vinyl chloride or chlorosulfonated polyethylene, thermoplastic resin such as polystyrene, polyethylene, polypropylene, vinyl chloride or ethylene-vinyl acetate copolymer resin (EVA) Gels such as silicon, emulsions such as vinyl acetate, EVA or acrylic resin, rubber latex, and the like.

  The piezoelectric material 1b is a member that exhibits a piezoelectric effect. The piezoelectric material 1b generates an electric field by generating electric polarization according to the stress when a mechanical stress is applied (positive effect), and generates a distortion according to the magnitude of the electric field when the electric polarization is generated by applying the electric field. The piezoelectric effect (reverse effect) is shown. The piezoelectric material 1b is, for example, piezoelectric ceramic particles such as lead zirconate titanate (PZT), lead titanate, lead metaniobate, or barium titanate.

  The electrode portions 2 </ b> A and 2 </ b> B are contact portions that are electrically connected to the piezoelectric rubber 1. The electrode portions 2A and 2B are laminated on both sides of the piezoelectric rubber 1, and are formed so as to cover the entire area of both sides of the piezoelectric rubber 1. The electrode portions 2A and 2B are formed by applying a conductive adhesive such as a silver paste in which a conductive filler such as silver powder is dispersed in an organic binder such as an epoxy resin on both surfaces of the piezoelectric rubber 1, for example. The electrode portions 2A and 2B are respectively connected to conductive portions such as electric wires through which a current generated by the piezoelectric rubber 1 flows.

Next, a method for recovering a piezoelectric material according to an embodiment of the present invention will be described.
The recovery method # 100 shown in FIGS. 2 and 3 is a method of recovering the piezoelectric material 1b from the piezoelectric rubber 1. The collection method # 100 separates and collects the piezoelectric material 1b from the piezoelectric rubber 1 by utilizing the difference in decomposition temperature of each composition constituting the piezoelectric rubber 1 and the difference in particle diameter of the decomposition residue 5. The recovery method # 100 includes a removal step # 110, a cutting step # 120, a thermal decomposition step # 130, a separation step # 140, and the like.

  The removal step # 110 is a step of removing the electrode portions 2A and 2B from the piezoelectric rubber 1 with the organic solvent S. In the removal step # 110, for example, the electrode portions 2A and 2B are dissolved by the removing device 3 as shown in FIG. 4B, and the electrode portions 2A and 2B are removed from the piezoelectric rubber 1 shown in FIG. . The removing device 3 shown in FIG. 4B is a device that removes the electrode portions 2A and 2B from the piezoelectric rubber 1. The removal device 3 includes a storage tank 3a for storing the piezoelectric rubber 1 and the organic solvent S in a state where the electrode portions 2A and 2B are formed. The organic solvent S is, for example, a second type organic solvent such as acetone, isopropyl alcohol, ethyl ether, xylene, or toluene that can dissolve the silver paste forming the electrode portions 2A and 2B.

  Cutting process # 120 is a process of cutting the piezoelectric rubber 1. In the cutting step # 120, for example, as shown in FIG. 4C, the piezoelectric rubber 1 after the removal step # 110 is cut. In the cutting step # 120, the piezoelectric rubber 1 is finely cut to increase the surface area of the piezoelectric rubber 1 after cutting, thereby preventing oxygen in the piezoelectric material 1b in the piezoelectric rubber 1 from being consumed for combustion, and the piezoelectric material. It prevents the 1b from becoming brittle and causing the particles of the piezoelectric material 1b to be crushed and reduced.

  2 and 3 is a process of thermally decomposing the piezoelectric rubber 1 after the cutting process # 120. In the thermal decomposition step # 130, for example, the piezoelectric rubber 1 after the cutting step # 110 is pyrolyzed in the air by the thermal decomposition apparatus 4 as shown in FIG. 4D, and the organic matter in the piezoelectric rubber 1 is carbonized. Let The thermal decomposition apparatus 4 shown in FIG. 4D is an apparatus that thermally decomposes the piezoelectric rubber 1 in the air. The thermal decomposition apparatus 4 is, for example, an electric furnace that heats the piezoelectric rubber 1 using electricity as a heat source. The thermal decomposition apparatus 4 includes a housing portion 4a that houses the piezoelectric rubber 1 in the air, a resistor 4b that heats the inside of the housing portion 4a, a power supply portion 4c that supplies power to the resistor 4b, and a housing 4a. A temperature detection unit 4d that detects the temperature, a control unit 4e that controls the power supply unit 4c such that the current flowing through the resistor 4b changes based on the detection result of the temperature detection unit 4d, and the like are provided. In the thermal decomposition step # 130, the organic rubber is thermally decomposed by heating the piezoelectric rubber 1 in the air relatively slowly at a temperature increase temperature of about 100 ° C./2h near the EPDM decomposition temperature of 400 ° C. In the thermal decomposition step # 130, if the thermal decomposition temperature is lower than 300 ° C, the thermal decomposition of the rubber material 1a may be incomplete and organic matter may remain. Therefore, the thermal decomposition temperature may be set to 300 to 500 ° C. preferable.

  The separation step # 140 shown in FIGS. 2 and 3 is a step of separating the piezoelectric material 1b from the decomposition residue 5 after the thermal decomposition step # 130. In the separation step # 140, for example, a single unit of the piezoelectric material 1b having a particle diameter exceeding a predetermined value in the decomposition residue 4 is separated and recovered by the separation device 6 as shown in FIG. Here, the decomposition residue 5 shown in FIG. 4E is a mixture of a carbide, an inorganic compound, and the piezoelectric material 1b. A separation device 6 shown in FIG. 4E is a device that separates the piezoelectric material 1 b from the decomposition residue 5. The separation device 6 is a classification device such as a screen sieve that sorts into a piezoelectric material 1b having a particle diameter exceeding a predetermined value, a piezoelectric material 1b having a particle diameter equal to or less than a predetermined value, and a decomposition residue 4 that is a carbide and an inorganic compound. Yes, a sieve with a predetermined size (granular mesh) is used.

Next, a method for reusing a piezoelectric material according to an embodiment of the present invention will be described.
The reuse method # 200 shown in FIGS. 2 and 6 is a method of reusing the piezoelectric material 1b collected from the piezoelectric rubber 1. In the reuse method # 200, the piezoelectric rubber 1 is manufactured by reusing the piezoelectric material 1b recovered by the recovery method # 100 of the piezoelectric material 1b. The reuse method # 200 includes a kneading step # 210, a molding vulcanization step # 220, an electrode formation step # 230, a polarization step # 240, and the like.

  The kneading step # 210 is a step of kneading the recovered piezoelectric material 1b with the raw rubber material 1c. In the kneading step # 210, for example, the piezoelectric material 1b recovered by the recovery method # 100 of the piezoelectric material 1b is kneaded with the raw rubber material 1c by the kneading apparatus 7 as shown in FIG. A kneading apparatus 7 shown in FIG. 6A is an apparatus for kneading the recovered piezoelectric material 1b, raw rubber material 1c, and compounding agent C. The kneading device 7 is configured to freely rotate the pair of kneading rollers 7a and 7b that knead the piezoelectric material 1b, the raw rubber material 1c, and the compounding agent C collected by rotating around the rotation shaft, and the pair of kneading rollers 7a and 7b. A storage chamber 7c for storage, a charging port 7d for charging the collected piezoelectric material 1b, raw rubber material 1c and compounding agent C into the storage chamber 7c, an outlet 7e for taking out the kneaded material 8 after kneading, and the like are provided. Here, the raw rubber material 1c is a raw rubber such as natural rubber or synthetic rubber in a state before vulcanization. Compounding agent C includes, for example, an enhancer that imparts hardness, tensile strength, wear resistance, and the like to piezoelectric rubber 1, and a filler (reinforcing material / bulking agent) that improves the properties and workability of piezoelectric rubber 1. A softener or plasticizer that imparts plasticity to the piezoelectric rubber 1, a vulcanizing agent that links rubber molecules with sulfur or an organic peroxide to change the viscosity to elasticity, and a vulcanization accelerator that shortens the vulcanization time; A vulcanization accelerator or activator that promotes the action of the vulcanizing agent, an antioxidant or ozone deterioration inhibitor that prevents oxidative degradation or ozone degradation, and a processing aid (tackifier or lubricant that improves processability)・ Dispersant). The kneaded material 8 is a mixture obtained by mixing and kneading the recovered piezoelectric material 1b, raw rubber material 1c, and compounding agent C. In the kneading step # 210, the collected piezoelectric material 1b, raw rubber material 1c and compounding agent C are mixed and kneaded so that the piezoelectric material 1b and compounding agent C are uniformly dispersed in the raw rubber material 1c, The kneaded material 8 is produced by cutting into a size.

  The molding vulcanization step # 220 shown in FIGS. 2 and 6 is a step of vulcanizing the kneaded material 8 after the kneading step # 210 to form the piezoelectric rubber 1. In the molding vulcanization step # 220, for example, the kneaded product 8 after the kneading step # 210 is heated and pressurized by a molding vulcanizer 9 as shown in FIG. Is formed into a piezoelectric rubber 1 having the following shape. A molding vulcanizer 9 shown in FIG. 6B includes a pair of molds 9a and 9b heated to a predetermined temperature. The molding vulcanizer 9 pressurizes the kneaded material 8 between a convex mold (upper mold) 9a and a concave mold (lower mold) 9b, and heats the piezoelectric rubber 1 for a predetermined time. Mold to the shape of

  The electrode forming step # 230 shown in FIGS. 2 and 6 is a step of forming the electrode portions 2A and 2B on the piezoelectric rubber 1 after the molding vulcanization step # 220. In the electrode forming step # 230, for example, an electrode forming apparatus 10 as shown in FIG. 6C applies a conductive adhesive such as a silver paste to both surfaces of the piezoelectric rubber 1 to form the electrode portions 2A and 2B. The electrode portions 2A and 2B are attached to both surfaces of the piezoelectric rubber 1. An electrode forming apparatus 10 shown in FIG. 6C applies a conductive adhesive to one surface of the piezoelectric rubber 1, and includes a nozzle 10a for applying the conductive adhesive to the other surface of the piezoelectric rubber 1. I have.

  The polarization processing step # 240 shown in FIGS. 2 and 6 is a step of polarizing the piezoelectric material 1b. A polarization processing device 11 shown in FIG. 6D is a device that performs polarization processing on the piezoelectric material 1b. The polarization processing device 11 includes a DC power source 11a that applies a voltage between the electrode portion 2A and the electrode portion 2B. In the polarization treatment step # 240, each piezoelectric material dispersed in the piezoelectric rubber 1 by applying an electric field E between the electrode portion 2A and the electrode portion 2B by the polarization treatment device 11 as shown in FIG. 1b is electrically polarized so that the direction of the dipole moment of each piezoelectric material 1b is the same.

  As shown in FIG. 2, when the piezoelectric material 1b is recovered from the piezoelectric rubber 1 by the recovery method # 100, the piezoelectric material 1b is recycled and the piezoelectric rubber 1 is manufactured by the reuse method # 200. When the piezoelectric material 1b is recovered from the recycled piezoelectric rubber 1, the piezoelectric material 1b is recovered again from the piezoelectric rubber 1 by the recovery method # 100, and the usable piezoelectric material 1b is recycled by the reuse method # 200. The reuse of the piezoelectric rubber 1 is repeated.

The piezoelectric material recovery method and its reuse method according to the embodiment of the present invention have the following effects.
(1) In this embodiment, the piezoelectric rubber 1 is cut in the cutting step # 120, the piezoelectric rubber 1 after the cutting step # 120 is pyrolyzed in the thermal decomposition step # 130, and the thermal decomposition step # 130 in the separation step # 140. The piezoelectric material 1b is separated from the subsequent decomposition residue 5. For this reason, for example, the piezoelectric material 1b is taken out from the piezoelectric rubber 1 used for a sensor, an actuator, etc. as a piezoelectric ceramic by a simple separation and recovery method using an electric furnace or sieve, and the piezoelectric material 1b is reused. Can do. In addition, by cutting the piezoelectric rubber 1 into fine pieces, the surface area of the cut piezoelectric rubber 1 is increased to prevent oxygen shortage during thermal decomposition. For this reason, it is possible to prevent oxygen in the piezoelectric material 1b in the piezoelectric rubber 1 from being consumed for combustion as in the prior art 3, and also the piezoelectric material 1b becomes brittle and the piezoelectric material 1b Particles can be prevented from being crushed and reduced. Moreover, compared with the separation method using heavy liquid as in the prior art 1 and the separation method using acid or alkali as in the prior art 2, the environmental impact is reduced because the piezoelectric rubber 1 is thermally decomposed in the air. can do. Furthermore, the piezoelectric material 1b, which contains lead and is difficult to dispose of, can be safely separated and recovered from the piezoelectric rubber 1, and a useful technique for disposing of lead-containing substances can be provided.

(2) In this embodiment, the electrode portions 2A and 2B are removed from the piezoelectric rubber 1 by the organic solvent S in the removal step # 110, and the piezoelectric rubber 1 after the removal step # 110 is cut in the cutting step # 120. For this reason, for example, when the electrode portions 2A and 2B are formed by a conductive adhesive such as silver paste, handling is easier than when the electrodes are removed by nitric acid as in the prior art 3. The electrode portions 2A and 2B can be easily wiped and removed by the organic solvent S.

(3) In this embodiment, the organic rubber is thermally decomposed by heating the piezoelectric rubber 1 in the air in the thermal decomposition step # 130. For example, even when an organic solvent such as the prior art 3 is used, the crosslinked rubber such as the rubber material 1a of the piezoelectric rubber 1 cannot be dissolved. In this embodiment, when recovering the piezoelectric material 1b from the crosslinked rubber material 1a, the rubber material 1a can be decomposed by heat treatment without using an organic solvent. Further, by thermally decomposing the piezoelectric rubber 1 in the air, it is possible to completely burn the carbon and prevent the carbon from adhering to the piezoelectric material 1b.

(4) In this embodiment, in the separation step # 140, the decomposition residue 5 whose particle diameter exceeds a predetermined value is recovered as the piezoelectric material 1b among the decomposition residues 4. For this reason, the piezoelectric material 1b can be easily screened using the particle diameter of the piezoelectric material 1b, and only the piezoelectric material 1b can be recovered from the decomposition residue 4. In addition, the piezoelectric material 1b having a particle diameter equal to or less than a predetermined value can be removed, and the zinc oxide blended in the piezoelectric rubber 1 as a vulcanization accelerating agent or completely removed in the removal step # 110. Conductive adhesives such as silver paste that could not be removed can also be removed.

(5) In this embodiment, the recovered piezoelectric material 1b is kneaded with the raw rubber material 1c in the kneading step # 210, and the kneaded product 8 after the kneading step # 210 is vulcanized in the molding vulcanization step # 220 to piezo-electric rubber 1. To form. For this reason, the piezoelectric rubber 1 can be manufactured by reusing the collected piezoelectric material 1b. Further, since the piezoelectric rubber 1 can be formed simply by reusing the expensive piezoelectric material 1b and kneading with the new raw rubber material 1c and the compounding agent C, the piezoelectric rubber 1 can be manufactured at low cost.

(6) In this embodiment, the electrode portions 2A and 2B are formed on the piezoelectric rubber 1 after the molding vulcanization step # 220 in the electrode formation step # 230. Therefore, the electric power generated when the molded and vulcanized piezoelectric rubber 1 is deformed can be taken out from the electrode portions 2A and 2B, and the piezoelectric rubber 1 is supplied by supplying electric power to the electrode portions 2A and 2B from the outside. Can be deformed.

(7) In this embodiment, the piezoelectric rubber 1 is polarized in the polarization treatment step # 240. Therefore, an electric field E is applied to the piezoelectric material 1b that has lost its piezoelectric performance when the piezoelectric rubber 1 is thermally decomposed in the thermal decomposition step # 130, and the piezoelectric material 1b is electrically polarized to impart piezoelectric performance to the piezoelectric rubber 1. be able to.

(8) In this embodiment, the piezoelectric material 1b recovered by the recovery method # 100 of the piezoelectric material 1b is kneaded with the raw rubber material 1c in the kneading step # 210. For this reason, the piezoelectric material in the piezoelectric rubber 1 can be separated and recovered and reused, and a consistent process from the production of the piezoelectric rubber 1 to the material recycling can be constructed.

The present invention is not limited to the embodiment described above, and various modifications or changes can be made as described below, and these are also within the scope of the present invention.
(1) In this embodiment, the case where the electrode portions 2A and 2B are formed using a conductive adhesive such as silver paste has been described as an example. However, gold powder, copper powder, nickel powder, aluminum powder, plating powder, The electrode portions 2A and 2B can also be formed by a conductive adhesive in which a conductive filler such as carbon powder or graphite powder is dispersed in an organic binder such as epoxy resin, urethane resin, silicone resin, acrylic resin, or polyimide resin. . In this embodiment, the case where the piezoelectric rubber 1 is immersed in the organic solvent S in the removing step # 110 has been described as an example. However, the surface of the piezoelectric rubber 1 is wiped off with the organic solvent S, and the electrode portions 2A and 2B. Can also be removed.

(2) In this embodiment, the case where the piezoelectric rubber 1 is molded by direct pressure molding (compression) in the molding vulcanization step # 220 has been described as an example. However, the rubber material 1a is forcibly injected into the mold. The piezoelectric rubber 1 can also be molded by pressure injection molding (transfer) or injection molding (injection) in which a rubber material 1a is injected into a mold. In this embodiment, the case where the electrode portions 2A and 2B are formed by applying a conductive adhesive to both surfaces of the piezoelectric rubber 1 with the nozzle 10a in the electrode forming step # 230 has been described as an example. The electrode portions 2A and 2B can also be formed by forming an adhesive on both surfaces of the piezoelectric rubber 1 by a method such as printing.

DESCRIPTION OF SYMBOLS 1 Piezoelectric rubber 1a Rubber material 1b Piezoelectric material 1c Raw rubber material 2A, 2B Electrode part 3 Removal apparatus 4 Thermal decomposition apparatus 5 Decomposition residue 6 Separation apparatus 7 Kneading apparatus 8 Kneaded material 9 Molding vulcanization apparatus 10 Electrode forming apparatus S Organic solvent C Compounding Agent

Claims (6)

A piezoelectric material recovery method for recovering a piezoelectric material from piezoelectric rubber,
A removing step of removing the electrode portion from the piezoelectric rubber with an organic solvent;
A cutting step of cutting the piezoelectric rubber after the removing step ;
A pyrolysis step of pyrolyzing the piezoelectric rubber after the cutting step;
A separation step of separating the piezoelectric material from the decomposition residue after the thermal decomposition step;
Method for recovering piezoelectric material including In the recovery method of the piezoelectric material according to claim 1,
The pyrolysis step includes a step of thermally decomposing an organic compound by heating the piezoelectric rubber in air;
A method for recovering a piezoelectric material characterized by the above. A piezoelectric material recovery method for recovering a piezoelectric material from piezoelectric rubber,
A cutting step of cutting the piezoelectric rubber;
A pyrolysis step of pyrolyzing the piezoelectric rubber after the cutting step;
And a separation step of separating the piezoelectric material from degradation residue after the pyrolysis step,
The separation step includes a step of recovering, as the piezoelectric material, a decomposition residue having a particle diameter exceeding a predetermined value among the decomposition residues;
A method for recovering a piezoelectric material characterized by the above . A method of reusing a piezoelectric material that reuses a piezoelectric material recovered from a piezoelectric rubber,
A kneading step of kneading the recovered piezoelectric material with a raw rubber material;
Including a molding vulcanization step of vulcanizing the kneaded product after the kneading step to form the piezoelectric rubber,
The kneading step includes a step of kneading the piezoelectric material collected by the piezoelectric material collecting method according to any one of claims 1 to 3 with a raw rubber material,
A method of reusing a piezoelectric material characterized by the above. In the recycling method of the piezoelectric material according to claim 4 ,
Including an electrode forming step of forming an electrode portion on the piezoelectric rubber after the molding vulcanization step;
A method of reusing a piezoelectric material characterized by the above. In the recycling method of the piezoelectric material according to claim 4 or 5 ,
Including a polarization treatment step of polarization treatment of the piezoelectric rubber,
A method of reusing a piezoelectric material characterized by the above.

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