Adhesion and removal methods

Abstract

To provide a method of repeating adhesion and peeling by making adhesion force between adherents change.SOLUTION: In a method of adhesion and peeling controlling the amount of liquid 3 at the interface between adherents, a cycle of adhesion and peeling having an adhesion step in which at least one of the adherents has a plurality of pores 4, and, through the pores 4, the liquid 3 is supplied to the interface of the adherents to generate adhesion force between the adherents, and a step in which through the pores 4, the liquid 3 between the adherents is sucked back or by further increasing the liquid 3 in the interface of the adherents to peel is repeated.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a bonding and peeling method in which the adhesive strength is changed by controlling the amount of liquid supplied to the interface of adherends. [Background technology]

[0002] In recent years, the number of areas in which robots are playing an active role instead of humans has expanded dramatically. However, it is extremely difficult for robots to defy gravity and move freely along walls and ceilings in the same way that humans can. About 20 years ago, a method was reported for mimicking the strong adhesive properties of the fine hierarchical micro- and nano-scale structures on the surface of gecko limbs (Reference 1: K. Autumn et al., Nature, 405, 681-685 (2000) and Reference 2: AK Geim et al., Nature Materials, 2, 461-463 (2003)), and a great deal of research has been conducted, including by companies.

[0003] However, in order to move on walls or ceilings, the adhesive strength between the adherends must be changed from a strong state to a weak state, and then this process must be repeated, which has not yet been achieved. Some methods use suction to ensure adhesion by moving the contact surface, such as with automatic window cleaners, but this requires large-scale vacuum exhaust equipment and requires a large amount of electricity.

[0004] Patent Document 1 discloses a technique in which a liquid is exuded through pores in an adsorption plate to the interface between the substrate and the adsorption plate, and the substrate and the adsorption plate are bonded together by utilizing the surface tension of the liquid. However, because the pressure is increased by heating the liquid, causing it to seep out to the interface, there was a problem in that it became difficult to control the amount of liquid at the interface, and therefore the adhesive strength. In particular, when peeling off a substrate and bonding another substrate, the temperature and pressure fluctuate, making it impossible to precisely control the amount of liquid at the interface. Also, in order to weaken the adhesive force, a large vent hole separate from the pores is provided, and a special operation to release the pressure is required. Another problem is that this operation does not directly lead to a change in the amount of liquid at the interface of the adherend, i.e., a change in adhesive force. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP2002-154647 Summary of the Invention [Problem to be solved by the invention]

[0006] Currently, there is a demand for the development of a method for easily changing the adhesive strength between adherends and repeating adhesion and peeling. Therefore, an object of the present invention is to provide a method for repeating adhesion and peeling. [Means for solving the problem]

[0007] As a result of intensive research into solving the above problems, the inventors discovered a method of changing the adhesive strength between adherends by creating pores in at least one of the adherends and changing the amount of liquid that spreads through the pores to the interface of the adherends, thereby completing the present invention. In other words, the present invention is a method of adhesion and peeling in which the amount of liquid at the interface of adherends is controlled, characterized in that at least one of the adherends has a plurality of pores, and the amount of liquid at the interface of the adherends is changed through the pores, thereby changing the adhesive force between the adherends. By using this method, adhesion and peeling can be achieved by controlling the liquid at the interface of the adherend.

[0008] The present invention is also characterized by comprising a bonding process in which liquid is supplied to the interface of the adherend through pores to generate adhesive force between the adherends, and a first peeling process in which the liquid at the interface of the adherend is sucked back through the pores of the adherend to peel the adherends apart. By using this method, the liquid can be supplied to the interface of the adherend to effect adhesion, and the liquid can be sucked back to effect separation.

[0009] It is also characterized by comprising a bonding process in which liquid is supplied to the interface of the adherend through the pores to generate adhesive force between the adherends, and a second peeling process in which the amount of liquid at the interface of the adherend through the pores is increased to weaken the adhesive force between the adherends. By using this method, the amount of liquid between the adherends can be increased, weakening the adhesive force and enabling the materials to be peeled off.

[0010] Furthermore, the bonding process is characterized in that the temperature of the liquid is raised and the liquid is supplied to the interface of the adherend, and then the temperature of the liquid is lowered to increase the adhesive strength, and at the time of peeling, the temperature of the interface of the adherend is raised and then the amount of liquid at the interface of the adherend is changed through the pores, thereby changing the adhesive strength between the adherends. By using this method, a stronger adhesive strength can be obtained.

[0011] The bonding process is also characterized in that after supplying liquid to the interface of the adherends, at least one of the adherends is slid horizontally to reduce the amount of liquid at the interface of the adherends, thereby increasing the adhesive force between the adherends. By using such a method, the adhesive strength can be increased efficiently.

[0012] The present invention is also characterized in that a cycle of the bonding step and the first peeling step or the bonding step and the second peeling step is repeated. This method makes it possible to repeatedly bond and peel the material by controlling the liquid at the interface of the adherend. Effect of the Invention

[0013] By controlling the amount of liquid at the interface of the adherend of the present invention, it is possible to repeat adhesion and peeling. Furthermore, by appropriately utilizing the method of repeated adhesion and peeling of the present invention, it is possible to create a robot that can move quietly along ceilings, walls, etc. and remain in place with low energy consumption. [Brief description of the drawings]

[0014] [Figure 1] 1A to 1C are diagrams illustrating a method for repeating a bonding and peeling process. [Diagram 2]This is a diagram showing the state of the liquid at the interface between two opposing flat plates, viewed from the horizontal direction of the plates. [Diagram 3] 1A to 1C are diagrams illustrating a series of operations for bonding and peeling using a liquid supply device. [Figure 4] 13A and 13B are diagrams illustrating an operation in which liquid is supplied to the interface of the adherend, a flat adherend is placed on the adherend, and then the adherend is slid horizontally to reduce the amount of liquid at the interface of the adherend. [Diagram 5] This is a graph showing the measurement of the change over time in the upward load acting on the porous adherend when the flat adherend is lifted up after a porous adherend is placed on the bottom and a flat adherend on the top. [Figure 6] This figure shows the measured change in the upward load acting on the porous adherend over time when liquid was supplied to the surface of the porous adherend, a flat adherend was placed on it, and then the excess liquid was sucked back and the flat adherend was lifted up. [Figure 7] This is a graph showing the measurement of the change over time in the upward load acting on a porous adherend when a large amount of liquid was allowed to seep onto the surface of the porous adherend and the flat adherend was then lifted up. [Figure 8] This figure shows the measured change in the upward load acting on the porous glass adherend over time when liquid was supplied to the surface of the porous glass adherend, a flat adherend was placed on it, and then the excess liquid was sucked back and the flat adherend was lifted up. [Figure 9] This figure shows the adhesive force between the glass plate and the flat adherend measured by supplying a liquid to the surface of the glass plate, placing a flat adherend on it, and then sliding the glass plate horizontally, and applying a tensile force in the opposite direction to the flat adherend. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The present invention will now be described in further detail. Figure 1 is a diagram explaining the method of repeating the adhesion and peeling process. It shows a method of changing the adhesive force by controlling the amount of liquid at the adherend interface using an adherend having fine pores.

[0016] Fig. 1(A) shows that one adherend (porous adherend) 1 has perpendicular pores passing through it, and the other is a flat adherend 2. The upper side of Fig. 1(A) is the porous adherend 1, which is perforated with a number of pores 4. The lower side of Fig. 1(A) is the flat adherend 2, which in the present invention is a smooth glass plate or the like. In Fig. 1(A), no liquid is supplied between the adherends. Fig. 1(B) shows how liquid 3 is allowed to seep through pores 4 in porous adherend 1 to the interface between porous adherend 1 and flat adherend 2, generating adhesive force between the adherends. Liquid 3 is supplied to pores 4 in Fig. 2(B). This operation of generating adhesive force is called the bonding process.

[0017] Figure 1(C) shows how the liquid 3 between the adherends is sucked back through the pores 4 of the porous adherend 1, eliminating the wetness at the adherend interface, and the adherends are peeled off. At this time, there is no liquid 3, or very little liquid 3 remaining, which contributes to adhesion at the interface between the porous adherend 1 and the flat adherend 2. This operation of sucking back the liquid 3 is called the first peeling step. Fig. 1(D) shows the adherends being peeled off by increasing the amount of liquid 3 between the adherends through the pores 4 of the porous adherend 1 and decreasing the adhesive strength at the interface. The operation of increasing the amount of liquid 3 between the adherends and decreasing the adhesive strength is called the second peeling step.

[0018] In these operations, a cycle of adhesion and peeling can be repeated by alternately repeating the operations of Figures 1(B) and 1(C) or by alternately repeating the operations of Figures 1(B) and 1(D). That is, in the method of repeating adhesion and peeling of the present invention, at least one of the two or more adherends has pores, and the adhesive strength is changed by changing the amount of liquid at the interface between the adherends through the pores.

[0019] Figure 2 shows the state in which the interface of a flat plate is wetted with a liquid, as viewed from the horizontal direction of the plate. In the figure, θ is the contact angle of the liquid on the surface of the flat plate, and h is the film thickness of the liquid. Generally, the suction force of a liquid that wets the inside of a capillary is expressed by Laplace's law (Reference 3: Chikazawa et al., Interface Chemistry (Maruzen Publishing)). If the suction force of the liquid present at the interface of the flat plate is taken as the adhesive force, and Laplace's law is expressed in terms of the surface tension of the liquid γ, the contact angle of the liquid at the interface of the adherend θ, and the film thickness of the liquid at the interface of the adherend h, then we obtain formula (1). ΔP = 2γCosθ / h (1)

[0020] where ΔP is the adhesive force between the plates due to the liquid. Equation (1) shows that the adhesive force between the plates depends on the thickness (h) of the liquid present at the interface, and the thinner the film thickness (h), the stronger the adhesive force.

[0021] In other words, the adhesion and peeling methods can be carried out by a bonding process in which liquid 3 is spread on the interface of the adherend to develop an adhesive force corresponding to the film thickness h, and a peeling process in which the liquid spread on the interface of the adherend is sucked back or the film thickness h of the liquid at the interface is increased to reduce the adhesive force.

[0022] The structure of the pores 4 in the porous adherend 1 may be such that the liquid 3 can seep out onto the bonding surface through the pores 4. For example, through holes are opened in the porous adherend 1, and the liquid 3 is supplied to the porous adherend 1 through the through holes and allowed to seep out onto the bonding surface. Since the adhesive force based on the liquid 3 increases as the film thickness h at the interface between the adherends becomes thinner, it is necessary to allow a minute amount of the liquid 3 to seep out evenly onto the bonding surface.

[0023] Furthermore, if the number of pores 4 on the adhesive surface is small, it is difficult to spread the liquid 3 over the entire adhesive surface, so it is preferable for the adhesive surface to have multiple pores 4. The size of the pores 4 is not limited, but in order to finely adjust the supply amount of the liquid 3 and generate adhesive force with a thin layer of the liquid at the adherend interface, it needs to be 1 mm or less on average, and preferably 50 μm or less on average. If it is difficult to provide multiple pores 4 in the porous adherend 1, grooves can be dug in the adhesive surface to form flow paths, and the liquid can be spread over the adhesive surface along the flow paths.

[0024] Furthermore, the material of the porous adherend 1 having pores 4 may be any material as long as the desired pores 4 are formed therein, but it is preferable that the porous adherend 1 can be in close contact with the other flat adherend 2. From this point of view, it is preferable to use a flexible porous adherend 1 that can deform in correspondence with the surface of the other flat adherend 2. As shown in formula (1), it is desirable that the surface of the adherend has a small contact angle θ with the liquid 3 and high wettability. When using water or an aqueous solution as the liquid 3, for example, a film of anatase type titanium oxide is formed on the surface of the adherend, and then irradiated with ultraviolet light to make the surface superhydrophilic, thereby obtaining a strong adhesive force (Reference 4: R. Wang et al., Nature 388, 431 (1997)).

[0025] Any liquid 3 may be used as the liquid 3 developed on the interface of the adherend, so long as it can seep out or be absorbed back through the pores 4 of the porous adherend 1, but it is preferable to use a liquid with a high surface tension γ as shown in formula (1). In this respect, water has excellent properties. In order to obtain adhesion to a solid that easily repels water, it is preferable to add a surfactant or the like to the water to reduce the contact angle θ in formula (1), or to use a liquid other than water that easily wets the solid.

[0026] The force that bonds the adherend with the liquid 3 can also be said to be the force that holds the adherend still with the liquid, so the adhesive force also depends greatly on the fluidity and viscosity of the liquid. For this reason, it is also preferable to control the fluidity and viscosity within a range that allows fluidity to be exhibited in the pores of the adherend.

[0027] Any method can be used to supply the liquid 3 to the pores 4 formed in the porous adherend 1, but the film thickness must be controlled with high precision and as thin as possible. If gas is present in the supply line of the liquid 3, it becomes difficult to precisely control the supply amount due to fluctuations in the gas volume, so it is preferable to completely remove the gas from the liquid supply line. If the interface between the porous adherend 1 and the flat adherend 2 is smooth and has excellent adhesion, the adhesive strength can be increased by utilizing the suction of the liquid in the pores 4. At this time, the effect of sucking excess liquid 3 at the interface back into the pores 4 can also be obtained.

[0028] Here, the device (liquid supply device) for supplying and sucking the liquid 3, which repeats the actions of supplying and suctioning, utilizes a syringe and delivers and sucks the liquid by the reciprocating motion of a plunger (a movable pusher), and the movement of the plunger is highly controlled by machine.

[0029] This liquid supply device preferably uses multiple syringes with different volumes, for example a large-capacity syringe and a small-capacity syringe, and supplies the liquid 3 to the vicinity of the bonding surface of the porous adherend 1 at high speed using the large-capacity syringe, and then performs the operation of causing the liquid 3 to seep into the bonding surface and peeling off with high precision using the small-capacity syringe. The amount and precision of the liquid delivery depends on the size of the adherend used, but for example, two syringes with capacities of 5 mL and 0.25 mL are used, and operation is performed with a minimum liquid delivery volume of 1 μL.

[0030] FIG. 3 is a diagram illustrating a series of operations for bonding and peeling using a liquid supply device. In Fig. 3(A), a porous adherend 1 is placed on the bottom and a flat adherend 2 is placed on the top, with a liquid supply device 10 placed below the porous adherend 1. A large-capacity syringe 6 and a small-capacity syringe 7 are connected to a liquid supply line 5, and plungers 8 and 9, which change the amount of liquid in each syringe, can be moved back and forth with high precision. In FIG. 3(A), liquid 3 fills a portion of liquid supply line 5 as well as large-volume syringe 6 and small-volume syringe 7 . 3(B) to (F) have the same configuration as FIG. 3(A) except for the location where the liquid 3 is supplied.

[0031] FIG. 3(B) shows a state in which the liquid 3 is supplied to the liquid supply line 5 by pushing out the plunger 8 of the large-volume syringe 6, filling the porous adherend 1 with the liquid 3 up to near the surface thereof. FIG. 3(C) next shows a state in which the plunger 9 of the small-capacity syringe 7 is pushed out to supply a minute amount of liquid 3 to the liquid supply line 5, causing the liquid to permeate the surface of the porous adherend 1. The next Fig. 3(D) shows the state where the porous adherend 1 is pushed up and brought into contact with the flat adherend 2, and the opposing adherends are bonded and stationary. The operations in Fig. 3(B) to (D) constitute the bonding process. The bonding step may also involve contacting the porous adherend 1 with the flat adherend 2 and then allowing the liquid 3 to seep out from the porous adherend 1. In this case, the porous adherend 1 is pushed up from the state shown in Fig. 3(B) to come into contact with the flat adherend 2 as shown in Fig. 3(D), resulting in the liquid 3 seeping out to the interface as shown in Fig. 3(C).

[0032] 3(E) shows the state in which the plunger 9 is pulled back to suck back the liquid 3 at the interface of the adherends. This operation reduces the adhesive force at the interface of the adherends, and the opposing adherends are separated. Fig. 3(F) shows the state in which the plunger 9 is further pulled back to suck the liquid 3 in the porous adherend 1 back into the liquid supply line 5. The operations in Fig. 3(E) and (F) constitute the first peeling step. Figure 3(F) shows the same state as Figure 3(B), and when moving to the bonding process again, the bonding and peeling operations starting from Figure 3(C) can be performed at a different location on the flat substrate 2 by moving the porous substrate 1.

[0033] According to the present invention, the adhesive strength can also be reduced by increasing the amount of liquid 3 at the adherend interface through the pores 4 of the porous adherend 1. In this case, the series of operations is the same as that in Fig. 3, where Fig. 3(E) is replaced with Fig. 3(E'). Therefore, the operations in Fig. 3(E') and (F) constitute the second peeling step. Furthermore, after supplying the liquid 3 to the interface of the adherend through the pores 4 of the porous adherend 1, the adhesive strength can be increased by decreasing the fluidity of the liquid 3. In particular, by making the liquid non-fluid, strong adhesion can be obtained.

[0034] However, when peeling off the adherend, it is necessary to reduce the adhesive force by utilizing the pores 4 of the porous adherend 1. Any method can be used for this operation, but examples include a method of raising the temperature to supply liquid 3 to the interface, then lowering the temperature to reduce fluidity, and then raising the temperature again at the time of peeling to suck the liquid at the interface back through the pores 4, or a method of supplying a different liquid to the interface through different pores provided in the porous adherend 1 to change the adhesive force. For example, one method is to spread a highly viscous water-based liquid from one of the pores to the interface of the adherend to form a bond, and then supply water from the other pore during peeling, thereby increasing the film thickness of the liquid at the interface of the adherend and at the same time increasing its fluidity.

[0035] FIG. 4 is a diagram illustrating an operation in which liquid is supplied to the adherend interface, a flat adherend is placed on the adherend, and then the adherend is slid horizontally to reduce the amount of liquid at the adherend interface. FIG. 4(A) shows the same configuration as the porous adherend 1, flat adherend 2, liquid supply device 10, etc. shown in FIG. 3(A) and in the same operating state, so description thereof will be omitted. Fig. 4(B) shows the state in which the liquid 3 is supplied to the porous adherend 1 by pushing out the plunger 8 of the large-capacity syringe 6 and the plunger 9 of the small-capacity syringe 7, and the porous adherend 1 is brought into contact with the flat adherend 2 and left stationary. Compared to Fig. 3(D), the amount of liquid has increased.

[0036] Fig. 4(C) shows the state where the porous adherend 1 and the flat adherend 2 have slid horizontally against each other and then stopped. At this time, some of the liquid 3 between the adherends is attached to the sliding flat adherend 2, so the amount of liquid 3 between the adherends decreases, and the amount of liquid is the same as in the adhesive state shown in Fig. 3(D). The peeling process after adhesion is the same as that shown in FIG. 3(E) or FIG. 3(E'), and therefore the drawings and their explanations are omitted.

[0037] Hereinafter, the present invention will be specifically described by showing examples of control of adhesive strength, but the present invention is not limited to these in any way. Moreover, the liquid 3 used in Examples 1 to 4 is pure water.

[0038] Comparative Example 1 FIG. 5 is a graph showing the measurement of the change over time of the upward load acting on the porous adherend 1 when the flat adherend 2 is lifted up after the porous adherend 1 is placed on the bottom and the flat adherend 2 on the top. The vertical axis is the load and the horizontal axis is the time. The load on the porous adherend 1 is adjusted to be at zero. Before the measurement, the load is a negative value because the porous adherend 1 is subjected to the load of the flat adherend 2 and its fixings. As the flat adherend 2 is pulled upwards, the load on the porous adherend 1 decreases. The porous adherend 1 used in Comparative Example 1 is a stainless steel punched metal porous body with a mirror-polished surface, a pore diameter of 0.3 mm, a pore spacing of 0.6 mm, and external dimensions of 1 cm x 1 cm square and a thickness of 0.5 mm. The porous adherend 1 used in the following Examples 1 and 2 is the same.

[0039] After bonding the porous adherend material 1 on the bottom and the flat adherend material 2, which has a larger area, on the top in the atmosphere, the load generated on the porous adherend material 1 when the flat adherend material 2 was pulled upward was measured as a function of time. The difference between the stable load value after the flat adherend 2 is released and the peak load value observed before that corresponds to the adhesive strength.

[0040] As shown in Figure 5, when the measurement starts and the load of the flat adherend 2 and its fixings is applied, the load is a negative value, but as the flat adherend 2 is pulled up, the load decreases, and when the porous adherend 1 and the flat adherend 2 are separated, the load becomes zero. In other words, only the load of the porous adherend 1 remains. However, a slight positive load, i.e., a force pulling upward, was observed before reaching zero, which indicates that a slight adhesive force was generated between the porous adherend 1 and the flat adherend 2. In this Comparative Example 1, the load was about 4 g / cm 2 The adhesive strength was .

[0041] Example 1 Figure 6 shows the measurement of the change over time in the upward load acting on the porous adherend 1 when liquid 3 is supplied to the surfaces of the porous adherend 1 and the flat adherend 2, the flat adherend 2 is placed on it, and then the excess liquid 3 is sucked back and the flat adherend 2 is lifted up. The vertical axis is the load and the horizontal axis is the time. As in Figure 5, the load on the porous adherend 1 is adjusted to be at the zero scale. The porous adherend 1 was placed on the bottom and the flat adherend 2 on the top, with a gap between them, and liquid 3 from large-capacity syringe 6 and small-capacity syringe 7 of liquid supply device 10 was delivered to the back of porous adherend 1, causing liquid 3 to seep onto the surface of porous adherend 1, and then flat adherend 2 was bonded. After that, small-capacity syringe 7 was returned to suck back excess liquid 3 at the interface between porous adherend 1 and flat adherend 2, and the change over time in the upward load generated on porous adherend 1 when flat adherend 2 was lifted up was measured.

[0042] A liquid supplying device 10 was attached to the underside of the porous adherend 1, and 0.18 mL of liquid was delivered to cause the liquid 3 to seep out from the pores 4 of the porous adherend 1. After the porous adherend 1 and the flat adherend 2 were placed on top of each other, 0.09 mL of liquid was sucked up to suck back the excess liquid 3. In this Example 1, the liquid delivery amount and the liquid absorption amount are the set values ​​of the liquid supply device 10, and are not the increase or decrease in the amount of liquid 3 at the adherend interface. The change with time of the load generated on the porous adherend 1 when the flat adherend 2 was pulled upward was measured. The difference between the stable load value after the flat adherend 2 is released and the peak load value observed before that corresponds to the adhesive strength. In this Example 1, it is about 17 g / cm 2 The adhesive strength was .

[0043] Example 2 Figure 7 shows the measurement of the change over time in the upward load acting on the porous adherend 1 when a large amount of liquid 3 is allowed to seep onto the surface of the porous adherend 1 and the flat adherend 2 is then lifted up. The vertical axis in Figure 7 also represents the load, and the horizontal axis also represents time. As in Figure 5, the load on the porous adherend 1 is adjusted to be at the zero scale. When liquid 3 was allowed to seep onto the surface of porous adherend 1, a larger amount of liquid 3 was allowed to seep onto the surface of porous adherend 1, a flat adherend 2 was placed on it, and then the change over time in the upward load generated on porous adherend 1 when flat adherend 2 was lifted up was measured.

[0044] As in Example 1, the liquid supplying device 10 was attached to the back surface of the porous adherend 1, and 0.27 mL of liquid was delivered to cause the liquid to seep out from the pores 4 of the porous adherend 1. The flat adherend 2 was placed on top of it, and then the flat adherend 2 was pulled upward. The change over time in the load acting on the porous adherend 1 was measured. No clear peak was observed before the load stabilized after the adherends were separated, and almost no adhesive force was generated between the adherends.

[0045] Example 3 Figure 8 shows the measurement of the change over time in the upward load on the porous adherend 1 when liquid 3 is supplied to the surface of a 1 cm x 1 cm square, 1 mm thick glass porous adherend 1 with a fine arrangement of circular pores with a pore diameter of 25 μm and pore spacing of 31 μm, a flat adherend 2 is placed on it, and the excess liquid 3 is sucked back and the flat adherend 2 is lifted up. The vertical axis is the load and the horizontal axis is the time. As in Figure 5, the load on the porous adherend 1 is adjusted to be at the zero scale.

[0046] The porous adherend 1 was placed on the bottom and the flat adherend 2 on the top, with a gap between them, and liquid 3 from large-capacity syringe 6 and small-capacity syringe 7 of liquid supply device 10 was delivered to the back of porous adherend 1, causing liquid 3 to seep onto the surface of porous adherend 1, and then flat adherend 2 was bonded. After that, small-capacity syringe 7 was returned to suck back excess liquid 3 at the interface between porous adherend 1 and flat adherend 2, and the change over time in the upward load generated on porous adherend 1 when flat adherend 2 was lifted up was measured.

[0047] A liquid supplying device 10 was attached to the underside of the porous adherend 1, and 0.10 mL of liquid was delivered to cause the liquid to seep out from the pores 4 of the porous adherend 1. After the porous adherend 1 and the flat adherend 2 were placed on top of each other, 0.05 mL of liquid was sucked up to suck back the excess liquid 3. In this Example 3, the liquid delivery amount and the liquid absorption amount are the set values ​​of the liquid supply device 10, and are not an increase or decrease in the amount of liquid 3 at the adherend interface. The change with time of the load acting on the porous adherend 1 when the flat adherend 2 was pulled upward was measured.

[0048] The difference between the stable load value after the flat-plate adherend 2 is released and the peak load value observed before that corresponds to the adhesive strength. In this Example 3, it was about 41 g / cm 2 The adhesive strength was . The adhesive strength is greater compared to Example 1 because the glass porous adherend 1 has a smoother surface and a larger contact area compared to the stainless steel porous adherend 1, the pores 4 are smaller, allowing for high-precision control of the liquid 3, and the uniformity of the film thickness h is improved. Also, the time on the horizontal axis is different compared to Examples 1 and 2 because the stretch of the thread pulling the flat adherend 2 is different.

[0049] [Example 4] Figure 9 shows the adhesive force between the glass plate and the flat adherend measured by supplying liquid to the surface of the glass plate, placing a flat adherend on it, and then sliding the glass plate horizontally, measuring the tensile force applied in the opposite direction to the flat adherend as the adhesive force applied between the glass plate and the flat adherend. In this Example 4, instead of a porous adherend 1, liquid 3 was sprayed onto the surface of a flat glass plate (width 4.5 cm, length 15 cm) to an average thickness of approximately 40 μm using a sprayer, and a circular flat adherend with a diameter of 3 cm was placed on it.The flat glass plate was then slid horizontally at a speed of 1 cm / s, and the tensile force applied in the opposite direction to the circular flat adherend was measured as the adhesive force between the flat glass plate and the circular flat adherend. The vertical axis is the pulling force and the horizontal axis is the sliding distance. Since the sliding speed is 1 cm / s, the total time on the horizontal axis is 10 s.

[0050] As the amount of liquid between the adherends decreases due to horizontal sliding, the tensile force increases, reaching a maximum of approximately 110 g / cm per unit area of ​​the flat adherend. 2 It was confirmed that an adhesive strength of 100% was obtained. In FIG. 9, the sliding operation is stopped when the pulling force reaches a constant maximum, but if the sliding continues in this state, the pulling force will drop rapidly.

[0051] In the above Example 1, the load when the flat adherend 2 was pulled up was measured with the flat adherend 2 placed on the porous adherend 1 shown in (C) and (D) in Figure 3. If the opposing porous adherend 1 and flat adherend 2 are stationary, this adhesive force will be able to hold the lower porous adherend 1 if it is lightweight.

[0052] In Example 2, the load when the flat adherend 2 was pulled up was measured with the amount of liquid 3 further increased (FIG. 3(E')) from (D) in FIG. 3. This operation weakens the adhesive force, causing the porous adherend 1 to peel off. Furthermore, after peeling, the porous adherend 1 is moved to another location on the flat adherend 2 and the operation of Example 1 is carried out, making it possible to repeat the bonding and peeling steps and then the next bonding step.

[0053] In addition, in Example 3, the hole diameter of the pores 4 in the porous adherend 1 was changed, and the load when the flat adherend 2 was pulled up was measured with the flat adherend 2 placed on the porous adherend 1 as shown in (C) and (D) in Figure 3. As described above, the pores 4 of the porous adherend 1 must be 1 mm or less on average in order to generate adhesive force with a thin layer of liquid at the adherend interface, and are preferably 50 μm or less on average. In addition, if the porous adherend 1 is made of glass with perpendicular pores, the lower limit is about 6 μm, which is the limit of the manufacturing method, but if it is made of other materials, the lower limit of 10 nm is possible. It was confirmed that adhesive force can be obtained by controlling the amount of liquid 3 within the range of 0.3 mm to 25 μm, which is the hole diameter in Examples 1 and 3.

[0054] Example 4 did not use the porous adherend 1 used in Examples 1 to 3, but instead measured the increase in tensile force and the increase in adhesive strength per unit area by supplying a liquid to a flat glass plate, placing another flat glass plate on it, and then sliding the glass plates horizontally against each other. This Example 4 is based on the assumption that the amount of liquid is controlled and supplied from somewhere other than the porous adherend 1. However, even in this case, the porous adherend 1 is used in the peeling process for weakening the adhesive force, and the adhesive force is weakened by controlling the amount of liquid.

[0055] Any method may be used to supply the liquid 3 from a source other than the porous adherend 1, but it is preferable to use a sprayer in order to efficiently spread a small amount of liquid 3 on the surface of the adherend. When repeating adhesion and peeling, a small amount of liquid 3 is sprayed onto one adherend, the other adherend is placed on it, and the adherend is slid horizontally to obtain strong adhesion. Thereafter, liquid is supplied to the adherend interface from the pores of the porous adherend 1, weakening the adhesive force between the adherends and peeling the adherends off. It is assumed that adhesion and peeling will be repeated by repeating this operation.

[0056] In addition, the operations in Figures 3(E) and (E') show a state in which the porous adherend material 1 is lowered, which is the opposite to the embodiment in which the flat adherend material 2 is pulled up, but in terms of load measurement, it does not matter which one moves. In Comparative Example 1, the load was measured when the flat adherend 2 was placed on the porous adherend 1 and the flat adherend 2 was pulled upward with the liquid 3 in the state shown in Fig. 3(A) or (B). If the measurement was performed in the state shown in Fig. 3(B), this corresponds to the first peeling step in which the liquid 3 has been sucked back. [Explanation of symbols]

[0057] Reference Signs List 1 Porous substrate, 2 Flat substrate (glass plate), 3 Liquid, 4 Pore, 5 Liquid supply line, 6 Large capacity syringe, 7 Small capacity syringe, 8 Large capacity syringe plunger, 9 Small capacity syringe plunger, 10 Liquid supply device.

Claims

1. In a method of adhesion and debonding in which the amount of liquid at the adherend interface is controlled, At least one of the adherends has a plurality of pores, and the amount of liquid at the interface between the adherends is changed through the pores to change the adhesive strength between the adherends; A bonding and peeling method comprising a bonding step in which a liquid is supplied to the adherend interface through the pores to generate an adhesive force between the adherends, and a second peeling step in which the amount of liquid at the adherend interface through the pores is increased to weaken the adhesive force between the adherends.

2. The method of claim 1, A bonding and peeling method characterized in that the bonding process involves increasing the temperature of the liquid, supplying the liquid to the adherend interface, and then lowering the temperature of the liquid to increase the adhesive strength, and the second peeling process involves increasing the temperature of the adherend interface, and then increasing the amount of liquid at the adherend interface through the pores, thereby weakening the adhesive strength between the adherends.

3. In a method of adhesion and debonding in which the amount of liquid at the adherend interface is controlled, At least one of the adherends has a plurality of pores, and the amount of liquid at the interface between the adherends is changed through the pores to change the adhesive strength between the adherends; a bonding step in which a liquid is supplied to the interface of the adherend through the pores to generate an adhesive force between the adherends, and a first peeling step in which the liquid at the interface of the adherend is sucked back through the pores of the adherend to peel the adherends, A bonding and peeling method characterized in that the bonding process involves raising the temperature of the liquid, supplying the liquid to the adherend interface, and then lowering the temperature of the liquid to increase the adhesive strength, and the first peeling process involves raising the temperature of the adherend interface and then sucking back the amount of liquid at the adherend interface through the pores, thereby weakening the adhesive strength between the adherends.

4. The method for bonding and peeling according to any one of claims 1 to 3, The bonding and peeling method is characterized in that the bonding step involves sliding at least one of the adherends horizontally to reduce the amount of liquid at the interface between the adherends and increase the adhesive force between the adherends.

5. The method for bonding and peeling according to claim 4, A method for bonding and peeling, comprising repeating a cycle of the bonding step and the first peeling step or the bonding step and the second peeling step.

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