Adhesion separation method and adhesion separation device

Abstract

To provide an adhesion / peeling method and an adhesion / peeling device with which an adherend can be peeled off without any residue after the adherend has been adhered to a non-conducting fixation target object.SOLUTION: In an adhesion / peeling method according to an embodiment, one face side of an adhesive sheet, having adhesiveness on the one face side and on the other face side and formed of an electrically peelable adhesive of which the adhesiveness is lowered based on an input voltage, is adhered to a predetermined position of a fixation target object, a first electrode of an adherend having the first electrode formed of a conductor is adhered to the other face side of the adhesive sheet, a second electrode, to a surface of which conductivity is imparted at the predetermined position of the object fixation target by impregnating the predetermined position thereof into a liquid, is temporarily formed. By inputting a predetermined voltage between the first and second electrodes, the adhesive sheet is peeled off from the fixation target object.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] FIELD OF THE INVENTION An embodiment of the present invention relates to a method and an apparatus for debonding. [Background technology]

[0002] For example, when temporarily adhering a sensor to concrete, adhesives or double-sided tape are generally used. However, when the sensor is removed, residues of the adhesive or double-sided tape may remain on the concrete. When an article to be adhered is temporarily adhered to a fixed object and then removed again, it is desirable that no residues of adhesive or the like remain on the fixed object.

[0003] In recent years, adhesives that can be easily peeled from adherends by applying a voltage have been put to practical use. However, this technology requires that both the object to be fixed and the object to be adhered have electrical conductivity, which limits the range of application. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-037354 [Patent Document 2] International Publication No. 2021 / 166803 Summary of the Invention [Problem to be solved by the invention]

[0005] The problem to be solved by the present invention is to provide a method and apparatus for bonding and separating an object to be bonded to a non-conductive object, and then separating the object without leaving any residue. [Means for solving the problem]

[0006] In one embodiment of the adhesive peeling method, one side of an adhesive sheet formed from an electrically peelable adhesive that has adhesiveness on one side and the other side and whose adhesiveness decreases based on the input of voltage is adhered to a predetermined position on an object to be fixed, the first electrode of an adherend having a first electrode formed from a conductor is adhered to the other side of the adhesive sheet, a liquid is impregnated into the predetermined position, a second electrode that has been made conductive is temporarily formed on the surface of the object to be fixed at the predetermined position, and the adhesive sheet is peeled off from the object to be fixed by inputting a predetermined voltage between the first electrode and the second electrode. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a diagram showing the relationship between the moisture content of concrete and its resistivity. [Figure 2] FIG. 2 is a cross-sectional view showing a configuration assumed for adhesion and separation in the first embodiment. [Figure 3] 3A to 3C are cross-sectional views showing one step of the adhesion / peel method according to the first embodiment. [Figure 4] 3A to 3C are cross-sectional views showing one step of the adhesion / peel method according to the first embodiment. [Figure 5] 3A to 3C are cross-sectional views showing one step of the adhesion / peel method according to the first embodiment. [Figure 6] 3A to 3C are cross-sectional views showing one step of the adhesion / peel method according to the first embodiment. [Figure 7] FIG. 6 is a cross-sectional view showing one step of the adhesion / peel method according to the second embodiment. [Figure 8] FIG. 6 is a cross-sectional view showing one step of the adhesion / peel method according to the second embodiment. [Figure 9] FIG. 6 is a cross-sectional view showing one step of the adhesion / peel method according to the second embodiment. [Figure 10] FIG. 6 is a cross-sectional view showing one step of the adhesion / peel method according to the second embodiment. [Figure 11] FIG. 10 is a perspective view showing the adhesive / peel device according to the second embodiment before a power supply unit is connected. [Figure 12] FIG. 10 is a perspective view showing the adhesive / peel device according to the second embodiment after the power supply unit is connected. [Figure 13] FIG. 10 is a cross-sectional view showing the adhesive peeling device according to the third embodiment before a power supply unit is connected. [Figure 14] FIG. 10 is a cross-sectional view showing the adhesive peeling device according to the third embodiment after the power supply unit is connected. [Figure 15] FIG. 10 is a cross-sectional view showing an adhesive peeling device according to a fourth embodiment before a power supply unit is connected. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an embodiment of a method and apparatus for peeling adhesion will be described with reference to the drawings.

[0009] (First embodiment) In order to inspect the condition of a concrete structure, a sensor is adhered to the surface of the structure, and after the inspection is completed, the sensor is peeled off and the structure is restored to its original state. The adhesion / peeling method of the embodiment is applied to such a case, in which an adherend is temporarily adhered to a fixed object, and then the non-adhered object is peeled off from the fixed object. Concrete is a building material made by mixing cement, water, sand, and gravel and solidifying it. Concrete has good insulating properties in a dry state. Concrete is porous and can absorb moisture.

[0010] As shown in Figure 1, concrete is known to have resistive properties when it absorbs moisture. Mortar, which is made by removing gravel from the concrete composition, also has similar properties. Based on this property, concrete or mortar can be used as a temporary electrically conductive electrode when it is impregnated with water, electrolyzed water, or the like and kept in a moist state.

[0011] As shown in Figure 2, the adhesive peeling device 100 used in the adhesive peeling method comprises an adhesive sheet 1 formed in a sheet shape, a first electrode 2 adhered to the adhesive sheet 1, concrete C formed on the second electrode 3 in a wet state, and a power supply unit 4 that inputs a predetermined voltage between the first electrode 2 and the second electrode 3.

[0012] The adhesive sheet 1 is a sheet having adhesiveness on one side 1A and the other side 1B. One side 1A of the adhesive sheet 1 is adhered to a predetermined position on concrete C, which is the object to be fixed. The other side 1B of the adhesive sheet 1 is adhered to a first electrode 2. The adhesive sheet 1 is made of an electrically releasable adhesive whose adhesiveness decreases when a voltage is applied.

[0013] An electro-releasable adhesive is, for example, a pressure-sensitive adhesive formed from an acrylic polymer, an ionic liquid containing an imidazolium salt, and a migration promoter. When a voltage is applied to an electro-releasable adhesive between an anode and a cathode, the imidazolium cations contained therein migrate to the cathode. As a result, hydrogen is generated at the cathode through a reduction reaction. The generated hydrogen bubbles separate the electro-releasable adhesive from the cathode, significantly reducing the adhesive strength of the electro-releasable adhesive on the cathode side. The size of the generated hydrogen bubbles is approximately 1 μm to 100 μm.

[0014] The pressure-sensitive adhesive sheet 1 of this embodiment may be made of other materials as long as they have electro-releasing properties that reduce adhesive strength based on the input of voltage. Depending on the peeling mechanism, electro-releasing adhesives come in two patterns: one in which the peeling surface occurs on the positive side of the input voltage, and the other in which the peeling surface occurs on the negative side. In this embodiment, either type of electro-releasing adhesive may be used. A voltage is input with a polarity that causes the peeling surface to face the object to be fixed.

[0015] The first electrode 2 is made of an electrically conductive material. For example, a sensor housing or the like is adhered to the first electrode 2 as described below. The first electrode 2 is electrically connected to the anode side of the power supply unit 4. The first electrode 2 is adhered to the other surface 1B of the adhesive sheet 1.

[0016] The second electrode 3 is a region of the concrete C that has been impregnated with a liquid such as water at a predetermined position and is formed to be temporarily electrically conductive while the liquid is maintained in a wet state. The liquid may contain at least one of conductive particles or ionic electrolytes to enhance electrical conductivity. The second electrode 3 is electrically connected to the cathode side of a power supply 4. The second electrode 3 is adhered to one surface 1A of the adhesive sheet 1. When applying a voltage to the second electrode 3, an auxiliary electrode 5 such as a metal or a wet sponge may be used.

[0017] As shown in FIG. 3 , a predetermined position of concrete C, which is an object to be fixed, is impregnated with a liquid such as water W and made wet. The water W is supplied to the predetermined position by, for example, spraying, pouring, or pressing a wet sponge against the concrete. The water W penetrates into the concrete C by capillary action. A conductive second electrode 3 is temporarily formed in the wetted area on the surface of the object to be fixed at the predetermined position. At this time, the wetness and electrical resistance of the second electrode 3 may be measured. In addition to concrete and mortar, the second electrode 3 may be made of other materials such as plaster, brick, tile, wood, stone, wallpaper, fabric, and artificial building materials, as long as the material can be impregnated with a liquid, can be temporarily kept wet, and can be electrically conductive.

[0018] As shown in Figure 4, one surface 1A of an adhesive sheet 1 is adhered to a predetermined position on concrete C where a second electrode 3 is temporarily formed. A first electrode 2 is adhered to the other surface 1B of the adhesive sheet 1. An adherend is adhered to the first electrode 2. In the example of Figure 4, the adhesive sheet 1 is formed so that its adhesiveness is reduced on the cathode side.

[0019] As shown in FIG. 5, when peeling off the adhesive sheet 1, a predetermined voltage is input between the first electrode 2 and the second electrode 3 by the power supply unit 4. The second electrode 3 becomes electrically conductive due to ions eluted in the water impregnated in the concrete C. An auxiliary electrode 5 may be provided between the power supply unit 4 and the second electrode 3. If the area of ​​the second electrode 3 is large, electrical contact with the power supply unit 4 may be provided at one or more locations to reduce the potential gradient caused by electrical resistance. The input voltage is preferably, for example, between 5 V and 100 V. The power supply unit 4 inputs the voltage with a polarity such that the peeling surface of the adhesive sheet 1 faces the concrete. The voltage is input as direct current. The voltage may also be input as alternating current.

[0020] As shown in Figure 6, the adhesive strength of the adhesive sheet 1 on one side 1A decreases and it peels off from the surface of the concrete C. This allows the adhesive sheet 1 to be peeled off from the concrete C together with the first electrode 2 without leaving any residue of the adhesive sheet 1 on the concrete C side. The adhesive sheet 1 allows the concrete C to be restored to its original state. The wet concrete C returns to a dry state by natural drying. The wet concrete C may also be returned to a dry state using a dryer. The peeling of the adhesive sheet 1 allows the adherend on the side of the first electrode 2 to be recovered.

[0021] Hereinafter, a description will be given of an embodiment that is a modification of the adhesion / peeling method in the first embodiment. In the following description, the same names and symbols are used for the same components as in the first embodiment, and duplicated descriptions will be omitted as appropriate.

[0022] (Second embodiment) In the steps of the adhesion / peel method in the first embodiment, the step of wetting the concrete C may be carried out after the pressure-sensitive adhesive sheet 1 has been adhered to the concrete C.

[0023] 7, one surface 1A of the adhesive sheet 1 is directly adhered to a predetermined position on dry concrete C. A first electrode 2 is adhered to the other surface 1B of the adhesive sheet 1.

[0024] As shown in FIG. 8, when the adhesive sheet 1 is peeled off, the concrete C around the adhesive sheet 1 is impregnated with a liquid such as water W. The area including the predetermined position of the concrete C is moistened by the capillary action of the water W, which penetrates around to the area including the surface that contacts one surface 1A of the adhesive sheet 1. The moistened area functions as the second electrode 3. The second electrode 3 is formed when the adhesive sheet 1 including the first electrode 2 (adherend) is adhered to the predetermined position of the concrete C.

[0025] As shown in Figure 9, a predetermined voltage is input between the first electrode 2 and the second electrode 3 by a power supply unit 4. The second electrode 3 becomes electrically conductive due to ions eluted in the water impregnated in the concrete C.

[0026] 10, the adhesive strength of the first surface 1A of the adhesive sheet 1 decreases, and the adhesive sheet 1 is peeled off from the surface of the concrete C. This allows the adhesive sheet 1 to be peeled off from the concrete C together with the first electrode 2, without leaving any residue of the adhesive sheet 1 on the concrete C. The above-described adhesion / peeling method may be used, for example, when adhering an AE (Acoustic Emission) sensor that detects elastic waves to the surface of a concrete structure, diagnosing the structure, and then peeling off the AE sensor.

[0027] As shown in FIG. 11, a cylindrical AE sensor S that detects elastic waves to diagnose a concrete structure is adhered to concrete C via an adhesive sheet 1. The AE sensor S is adhered to the concrete C. The AE sensor S is installed on a structure such as a bridge. In this case, the structure such as a bridge is the fixed object. The AE sensor S detects elastic waves generated from the structure and converts the elastic waves into an AE signal (voltage signal).

[0028] Specifically, the AE sensor uses a piezoelectric element having sensitivity in the range of, for example, 10 kHz to 1 MHz. AE sensors include a resonance type that has a resonance peak within a frequency range, a wideband type that suppresses resonance, and the like. The AE sensor S may be of any type. The AE sensor S may also have a built-in preamplifier. The AE sensor may detect elastic waves using a voltage output type, a resistance change type, or a capacitance type, and any of these detection methods may be used.

[0029] The AE sensor S has a sensitive surface, for example, on its bottom. A first electrode 2 is adhered to the bottom. The AE sensor S and the first electrode 2 are adhered to the adhesive sheet 1. In this case, if the bottom of the AE sensor S is made of a conductor such as metal, the bottom may be used as the first electrode 2. If the housing of the AE sensor S is formed integrally with the bottom, the housing may be used as the first electrode 2. In this case, the housing of the AE sensor S is adhered to the adhesive sheet 1. The first electrode 2 is adhered to the other surface 1B of the adhesive sheet 1. One surface 1A of the adhesive sheet 1 is adhered to the concrete C. The AE sensor S detects elastic waves propagating to the fixed object via the adhesive sheet adhered to the sensitive surface of the sensor, and is removed after measurement is completed.

[0030] As shown in FIG. 12, when the AE sensor S is removed, a liquid that serves as an electrolyte, such as water W, is supplied to the concrete C around the adhesive sheet 1. The concrete C around the adhesive sheet 1 is impregnated with water W and becomes wet, forming a conductive second electrode 3. A power supply 4 is electrically connected to the first electrode 2 and the second electrode 3. A voltage is input between the first electrode 2 and the second electrode 3. A ring-shaped auxiliary electrode 5 may be provided on the second electrode 3. The auxiliary electrode 5 is formed, for example, with a size that extends around the adhesive sheet 1 without contacting it. The auxiliary electrode 5 allows a voltage to be input to the second electrode 3 around the adhesive sheet 1 so as to achieve equipotential.

[0031] The power supply unit 4 inputs a voltage so as to reduce the adhesive strength of the adhesive sheet 1 on the side that contacts the concrete C. In the example of FIG. 12, the adhesive sheet 1 is configured so that the adhesive strength on the cathode side is reduced, and the cathode is connected to the second electrode 3 side. By inputting a voltage to the auxiliary electrode 5 and the housing of the AE sensor S or the first electrode 2, the adhesive sheet 1 can be peeled off from the concrete C without leaving any residue. According to the above-described method for peeling an object from another object, non-destructive testing can be performed without leaving any residue of adhesive or the like on the object to be fixed.

[0032] In the second embodiment, in order to facilitate penetration of water W between the first electrode 2 and the concrete C, the adhesive sheet 1 may be formed in a striped or matrix pattern with paths for the water W. In this case, the paths for the water W may be filled with a material that promotes capillary action, such as a fibrous sheet or a porous material. According to the adhesion / peeling method of the second embodiment, by bringing the porous material to be fixed, such as concrete C, into a wet state, the material is made conductive, and the adhesive sheet 1, which has electro-peeling properties, can be electrically peeled off.

[0033] (Third embodiment) As shown in FIG. 13, the AE sensor S may be adhered to the concrete C via a fixing member G. The fixing member G is formed, for example, in a cylindrical shape that covers the AE sensor S. The fixing member G includes, for example, a cylindrical portion G1 having a diameter larger than that of the AE sensor S, and a disk-shaped lid portion G2 that covers the top of the cylindrical portion G1. The lid portion G2 is provided with a pressing member G3 that presses the AE sensor S toward the concrete C. The pressing member G3 is formed, for example, from an elastic body such as elastically deformable rubber. The fixing member G is formed, for example, from a conductive material such as metal.

[0034] The cylindrical portion G1 of the fixing member G has a bottom end formed in a circular ring shape. The adhesive sheet 1 is formed, for example, in a circular ring shape to match the shape of the bottom end of the cylindrical portion G1. The fixing member G is adhered to the concrete C via the adhesive sheet 1. By adhering the fixing member G that holds the AE sensor S to the other side of the adhesive sheet 1, the AE sensor S can be held relative to the concrete C (fixed object) via the fixing member G. With the fixing member G fixed, the AE sensor S is pressed by the pressing member G3 in a direction in which the bottom contacts the concrete C.

[0035] The fixing member G is not limited to the above-mentioned shape, and may be formed in a shape that covers part of the AE sensor S, or in other shapes such as a gate shape or a cantilever shape, as long as it can hold the AE sensor S in contact with the concrete C.

[0036] As shown in FIG. 14 , when the AE sensor S is removed, a circular auxiliary electrode 5 is placed around the adhesive sheet 1 on the surface of the concrete C. The auxiliary electrode 5 is formed, for example, with dimensions that allow it to extend around the adhesive sheet 1 without contacting it. A liquid that serves as an electrolyte, such as water W, is supplied to the concrete C around the adhesive sheet 1. The concrete C around the adhesive sheet 1 is impregnated with the water W and becomes wet, forming a conductive second electrode 3. The auxiliary electrode 5 comes into electrical contact with the second electrode 3 based on the supply of water W.

[0037] A power supply unit 4 is electrically connected to the fixing member G (first electrode 2) and the auxiliary electrode 5. A voltage is input between the fixing member G (first electrode 2) and the auxiliary electrode 5 (second electrode 3) from the power supply unit 4. The auxiliary electrode 5 allows a voltage to be input to the second electrode 3 around the adhesive sheet 1 so as to achieve an equipotential.

[0038] The power supply unit 4 inputs a voltage so as to reduce the adhesive strength of the surface of the adhesive sheet 1 that contacts the concrete C. By inputting a voltage to the auxiliary electrode 5 and the fixing member G (first electrode 2), the adhesive sheet 1 can be peeled off from the concrete C without leaving any residue. According to the above-described method for bonding and peeling an object, non-destructive testing can be performed without leaving any residue of adhesive or the like on the object to be fixed.

[0039] (Fourth embodiment) As shown in Fig. 15, the auxiliary electrode 5 may be provided in advance on the adhesive surface (side 1A) of the adhesive sheet 1 that will be attached to the object to be fixed. The auxiliary electrode 5 is formed to have a width smaller than that of the first electrode 2. A non-conductor 6 is provided between the auxiliary electrode 5 and the adhesive sheet 1. The non-conductor 6 can prevent peeling between the auxiliary electrode 5 and the adhesive sheet 1 when a voltage is applied between the first electrode 2 and the second electrode 3.

[0040] In each of the above embodiments, the adhesion / debonding method may include a step of measuring at least one of the electrical resistance value, the water content, and the humidity of the atmosphere of the object to be fixed. If it is determined based on these measurements that the object to be fixed is sufficiently kept wet due to rainfall or the like in the natural environment and that the second electrode is generated in the natural environment, the step of impregnating the predetermined position with liquid may be omitted, and a predetermined voltage may be applied between the first electrode and the second electrode.

[0041] The adhesion / separation method of the above embodiment may be performed based on remote control of a mobile installation means such as a drone. A remote-controlled adhesion / separation method is suitable for temporarily installing a sensor on a large structure such as a bridge. In a remote-controlled adhesion / separation method, voltage may be input to the first electrode 2 and the second electrode 3 by wireless power supply. In this case, a coil sensor electrically connected to the first electrode 2 and the second electrode 3 may be provided, and an AC magnetic field may be emitted from the drone toward the coil sensor to generate an induced current in the coil sensor. A frequency conversion circuit, a DC conversion circuit, or the like may be provided between the coil sensor and the first electrode 2 and the second electrode 3 to convert the frequency of the AC voltage input to the first electrode 2 and the second electrode 3.

[0042] According to at least one of the embodiments described above, the adhesive peeling method involves adhering one side of an adhesive sheet formed from an electrically peelable adhesive that has adhesiveness on one side and the other and whose adhesiveness decreases based on the input of a voltage to a predetermined position on the concrete C, adhering a first electrode of an AE sensor S, which has a first electrode formed from a conductor, to the other side of the adhesive sheet, impregnating the predetermined position with water W, temporarily forming a second electrode that has been made conductive on the surface of the concrete C at a predetermined position, and applying a predetermined voltage between the first electrode and the second electrode to peel the adhesive sheet from the concrete C, thereby eliminating any residue after the adherend has been adhered to the concrete C.

[0043] As described above, according to the adhesion / peeling method, even if the object to be fixed, such as concrete, is non-conductive, the adherend adhered to the object to be fixed can be electrically peeled off without leaving any residue.

[0044] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention described in the claims and their equivalents. [Explanation of symbols]

[0045] 1...adhesive sheet, 1A...one side, 1B...other side, 2...first electrode, 3...second electrode, 4...power supply unit, 5...auxiliary electrode, 100...adhesion peeling device, C...concrete, G...fixing member, W...water

Claims

1. an adhesive sheet formed of an electrically releasable adhesive having adhesive properties on one side and the other side and whose adhesiveness decreases upon input of a voltage is adhered to one side of the adhesive sheet at a predetermined position on an object to be fixed; an adherend having a first electrode formed of a conductor, the first electrode being adhered to the other surface side of the pressure-sensitive adhesive sheet; An adhesive peeling method in which the adhesive sheet is peeled off from the object to be fixed by inputting a predetermined voltage between the first electrode and a second electrode that has been made conductive and is formed on the surface of the object to be fixed at the predetermined position when the object to be fixed is made wet.

2. The adhesive / debonding method according to claim 1 , wherein the second electrode is temporarily formed by impregnating the predetermined position of the object with a liquid.

3. The bonding and debonding method according to claim 2 , wherein the second electrode is formed in a state where the object to be bonded is bonded to the predetermined position.

4. The liquid is water. The method for peeling and bonding according to claim 2 or 3.

5. The adhesion / debonding method according to claim 2 , wherein the liquid contains at least one of conductive particles and an ionic electrolyte.

6. 6. The adhesion / peel method according to claim 1, wherein the object to be fixed is made of concrete or mortar.

7. measuring at least one of the electrical resistance value of the object, the moisture content, and the humidity of the atmosphere; The method for debonding according to claim 1 , further comprising inputting the predetermined voltage between the first electrode and the second electrode when it is determined that the second electrode is generated in a natural environment.

8. the adherend is a sensor that detects elastic waves, detecting the elastic waves propagating to the fixed object via the adhesive sheet adhered to the sensitive surface of the sensor; The method for debonding according to any one of claims 1 to 7.

9. a fixing member that is conductive and that holds the sensor is adhered to the other surface of the adhesive sheet, thereby holding the sensor relative to the object to be fixed; a conductive auxiliary electrode is electrically contacted with the second electrode; The adhesive peeling method according to claim 8 , wherein the predetermined voltage is input between the fixing member and the auxiliary electrode.

10. a first electrode formed of a conductor; an adhesive sheet having adhesive surfaces on one side and the other side; a power supply unit that inputs a predetermined voltage between a second electrode that has been given conductivity and is formed on a surface of a fixed object at a predetermined position to which the one side of the adhesive sheet is adhered, and the first electrode that is adhered to the other side of the adhesive sheet, thereby causing an electrochemical reaction in the adhesive sheet and peeling the adhesive sheet from the fixed object; Equipped with the second electrode is formed by bringing the predetermined position of the object to a wet state. Adhesion removal device.

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