JP7150422B2 - Electric adhesive sheet and its manufacturing method - Google Patents

Description

Application of Article 30, Paragraph 2 of the Patent Law Published on September 5, 2017 in the Lecture Proceedings of the 2017 Japan Society for Precision Engineering Autumn Conference

TECHNICAL FIELD The present invention relates to an electric adhesive sheet and its manufacturing method, and more particularly to an electric adhesive sheet applicable to a fixed conveying mechanism for fine parts and its manufacturing method.

Conventionally, in a fixing and conveying mechanism for an article, a vacuum chuck has been used to fix and convey an article by sucking on the surface of the article to be conveyed to create a vacuum state. It is also known to use an electrostatic chuck as means for holding and transporting a substrate, for example, in a semiconductor manufacturing process.

An electric adhesive sheet is manufactured using an ER gel, which is a gel of an ER fluid that exhibits a so-called electrorheological (hereinafter referred to as ER) effect, and holds an adherend by electrically adjusting the adhesiveness of the surface. . The ER fluid reversibly changes its viscoelasticity by changing the voltage applied to a colloidal solution in which fine particles are dispersed in an insulating liquid. The ER gel has a structure in which fine particles are dispersed in the gel, and can reversibly change the adhesiveness of the surface by changing the voltage.

When an electric adhesive sheet using ER gel is used, the ER gel is required to have a stable change in surface adhesiveness with changes in applied voltage, that is, an Electro-Adhesive effect (EA effect).

However, the performance of the ER gel greatly depends on the state of particle dispersion inside and on the surface, and the properties of the raw material ER fluid. ER fluid is usually in the form of dispersed phase particles (ER particles) dispersed in an electrically insulating dispersion medium such as silicone oil. was difficult to obtain. Moreover, it was difficult to uniformly disperse the ER particles and arrange the particles uniformly on the surface to form a gel, making it difficult to obtain a stable EA effect.

Therefore, in order to obtain a more stable EA effect, the application of a high-performance ER fluid and an ER gel with an enhanced electroadhesive effect (EA effect) by an electric field application manufacturing method have been proposed (for example, Patent Document 1 , 2).

Such an ER gel is an electrorheological fluid such as silicone oil, i.e., a silicone gel formed by gelling the ER fluid, and an organic-inorganic composite ER particle (for example, an acrylic resin fine particle as a core, and a semiconducting tin oxide particles coated with (for example, see Patent Document 3).

JP-A-2005-255701 JP 2008-266407 A JP-A-2001-26793

In the case of using the techniques described in Patent Documents 1 to 3 mentioned above, it was possible to apply them to a fixed conveying mechanism when the target object had a sufficient adhesive surface. However, there are still variations in the area where the electroadhesive effect can be obtained on the adhesive surface of the ER gel. is difficult, and sufficient and stable performance for actual fixed transport has not been obtained.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in order to solve the above-described problems, and it is an object of the present invention to provide an electric pressure-sensitive adhesive sheet capable of obtaining sufficient and stable adhesive strength so that, for example, articles can be fixedly conveyed. aim.

In order to solve the above-described problems, the present invention provides an electrical pressure-sensitive adhesive sheet using ER gel containing ER particles, wherein the ER gel containing ER particles is formed on the adhesive side surface of the electrical pressure-sensitive adhesive sheet. characterized by comprising a plurality of pillars formed by

According to the present invention configured in this way, since it has a plurality of pillars formed of ER gel, the tops of the pillars can be brought into contact with the article to be adhered. By bringing a plurality of pillars into contact with an article at the same time and holding the article with adhesive, for example, even if the adhesive strength of a certain pillar is low, the article can be adhesively held by the adhesive strength of the other pillars. As a result, even when the dispersibility of the ER particles is low, the electrical adhesive sheet as a whole can exhibit stable adhesive strength.
Furthermore, according to the present invention, it is also possible to transport a plurality of minute articles at the same time. That is, by using the above-described electric adhesive sheet having a plurality of pillars, a plurality of articles arranged at fixed positions can be adhered to the top of each of the plurality of pillars and conveyed.

Further, in order to solve the above problems, the present invention provides a method for producing an electrical pressure-sensitive adhesive sheet using ER gel containing ER particles, comprising forming a layer of ER gel containing ER particles on a conductive substrate, A template having a plurality of electrodes is placed at a position facing the surface of the ER gel layer, a voltage is applied to the electrodes to raise the ER gel from the ER gel layer, and the raised ER gel is cured. and

According to the present invention configured in this way, by forming a layer of ER gel containing ER particles on a conductive substrate and applying a voltage between the electrodes of the template and the conductive substrate, Pillars of ER gel can be formed corresponding to multiple electrodes. In the electric adhesive sheet having a plurality of pillars formed in this manner, the tops of the pillars can be brought into contact with the article to be adhered. By bringing a plurality of pillars into contact with an article at the same time and holding the article with adhesive, for example, even if the adhesive strength of a certain pillar is low, the article can be adhesively held by the adhesive strength of the other pillars. As a result, even when the dispersibility of the ER particles is low, the electrical adhesive sheet as a whole can exhibit stable adhesive strength.

As described above, according to the present invention, it is possible to obtain sufficient and stable adhesive strength so that, for example, articles can be fixedly conveyed.

1 is a side cross-sectional view of an electrical adhesive sheet according to an embodiment of the present invention; FIG. FIG. 4 is a flow diagram showing a manufacturing process of the electric pressure-sensitive adhesive sheet according to the same embodiment; It is a schematic diagram showing each process of the manufacturing stage of the electric pressure-sensitive adhesive sheet according to the same embodiment. 4 is a graph showing the relationship between electrode application time and voltage in the example of the present invention. 1 is a photograph of the surface of an electrical pressure-sensitive adhesive sheet produced according to Examples and Comparative Examples of the present invention. 4 is a graph showing the relationship between the holding force and voltage of the electric adhesive sheet according to the examples of the present invention.

Hereinafter, the electric pressure-sensitive adhesive sheet and the method for producing the same according to embodiments of the present invention will be described in detail. The electric pressure-sensitive adhesive sheet can be applied, for example, to devices for fixing and conveying fine parts such as semiconductor parts by machine, the surfaces of tools and gloves used by humans, and the like. The article to be adhered to the electric adhesive sheet is not limited to a conductive article, and may be a semiconductor or insulating article.

FIG. 1 is a side cross-sectional view of an electrical adhesive sheet according to an embodiment. The electric adhesive sheet 1 is mainly made of ER gel 3 , and ER particles 5 are dispersed in the ER gel 3 . A plurality of pillars 7 formed by processing the ER gel 3 are formed on the adhesive side surface of the electric adhesive sheet 1 that adheres to an adhesive object.

The ER gel 3 is made of a dielectric such as silicone oil that is easily deformed by Maxwell's stress and dielectrophoretic force. The ER gel 3 can be formed by cross-linking the silicone oil with a cross-linking agent to form a gel.

Examples of silicone oils include dimethylsilicone oils such as dimethylpolysiloxane, fluorine-modified silicone oils, and phenyl-modified silicone oils. These may be used individually by 1 type, and may use 2 or more types together. Examples of the fluorine-modified silicone oil include polysiloxane having a trifluoropropyl group (CF ₃ C ₂ H ₄ —), polysiloxane having a nonafluorohexyl group (C ₄ F ₉ C ₂ H ₄ —), and cyclic polysiloxane. and siloxane compounds.

The cross-linking agent added to the ER gel 3 includes, for example, a silicone oil end having a substituent having an unsaturated bond such as an aryl group, a methacryloyl group, an acryloyl group that reacts with heat, UV, etc., or a hydrogen atom at the end of the silicone oil. Hydrogensilicone, epoxy, glycidyl groups such as urethane, and silicone oils having condensation reactivity with isocyanate groups and having hydroxyl groups, amino groups, etc. at the ends are used.

As the ER gel 3, other than silicone gel, viscoelastic urethane rubber, butadiene rubber, acrylic rubber, olefin rubber, copolymers and modified products thereof may be used.

The ER particles 5 are formed, for example, by coating the surfaces of acrylic polymer particles having a diameter of about 100 nm to 20 μm with semiconductor tin oxide. The concentration of the ER particles 5 in the ER gel 3 is preferably 20-50% by weight, for example. The concentration of the ER particles 5 described above is an example, and the concentration of the ER particles 5 may be appropriately changed according to the adhesive force required for the electrical adhesive sheet 1 and the like.

Each of the plurality of pillars 7 has, for example, a cone shape with a height of about 100 μm and a diameter of 450 μm, and its top surface is formed substantially flat. The top surfaces of the pillars 7 act as the adhesive surfaces of the electrical adhesive sheet 1 . In addition, the plurality of pillars 7 are arranged regularly on the same plane, and when viewed from the direction in which the pillars 7 extend, for example, the pillars 7 are arranged at the corners of a square or at the corners of a rectangle. pillars 7 are preferably arranged in a grid pattern. Further, the distance between the plurality of pillars 7 formed on the adhesive surface side of the electric adhesive sheet 1 can be appropriately changed according to the adhesive force required for the electric adhesive sheet 1, but the distance between adjacent pillars 7 is It is preferred to determine as follows.

ここで、Ｅ_ｍａｘは電圧印加時の最大電場、Ｅ_ｍｉｎは電圧印加時の最小電場、Ｖは印加電圧、ε_０は真空中の誘電率、ε_ｐはＥＲゲルの比誘電率、σはＥＲゲルの表面張力を示す。そしてＸＹ平面上におけるピラー７同士の間隔は、Ｘ方向及びＹ方向の両方において上記式の値を満たすか、少なくとも一方向において上記式の値を満たしていればよい。即ち、例えば上記式により算出された値に基づいてＸ方向のピラー７同士の間隔Ｌを設定した場合、Ｙ方向のピラー７同士の間隔はＬとしても良いし、電圧にもよるが１００μｍ～１２００μｍの間で任意に決定された値としても良い。 The electrode adhesive sheet 1 exerts a holding force by applying a voltage, and the interval between the pillars 7 is determined according to the voltage and electric field applied when the adhesive object is adhered and held. be done. More specifically, the spacing λ between adjacent pillars 7 is preferably determined based on Equation 1 below.

Here, E _max is the maximum electric field when voltage is applied, E _min is the minimum electric field when voltage is applied, V is the applied voltage, ε ₀ is the dielectric constant in vacuum, ε _p is the relative dielectric constant of the ER gel, and σ is the ER Shows the surface tension of the gel. The distance between the pillars 7 on the XY plane should satisfy the value of the above formula in both the X direction and the Y direction, or satisfy the value of the above formula in at least one direction. That is, for example, when the distance L between the pillars 7 in the X direction is set based on the value calculated by the above formula, the distance between the pillars 7 in the Y direction may be set to L, or 100 μm to 1200 μm depending on the voltage. It may be a value arbitrarily determined between

By adjusting the interval between adjacent pillars 7 in consideration of the electric field, voltage, and properties of the ER gel applied when the object to be adhered is adhered and held, stable adhesion or holding force can be obtained. can be obtained.

Various shapes can be adopted as the shape of the pillar 7. As long as the top surface is substantially flat, a cylindrical shape or the like may be adopted in addition to the above-described conical shape. Also, the dimensions of the pillars 7 are not limited to those described above, and can be appropriately changed according to the size, weight, etc. of the object to be adhered.

Next, a method for manufacturing the electric adhesive sheet 1 will be described in detail. FIG. 2 is a flow diagram showing the method for producing an electrical adhesive sheet, and FIG. 3 is a schematic diagram schematically showing each step.

As shown in FIG. 2, in the series of processes of the method for manufacturing the electrical adhesive sheet 1, first, the ER gel 3 is prepared in step S1. More specifically, as shown in FIG. 3A, the ER gel 3 is prepared by mixing a predetermined amount of ER particles 5 and a cross-linking agent with a dielectric fluid such as silicone oil and stirring the mixture. executed.

Next, in the method for manufacturing the electric adhesive sheet 1, the layer 11 of the ER gel 3 is formed on the predetermined conductive substrate 9 in step S2. More specifically, in order to form the layer 11 of the ER gel 3, first, the ER gel 3 prepared in step S1 is placed on the surface of the substrate 9 as shown in FIG. to make the thickness of the ER gel 3 uniform. Thereby, a layer 11 of the ER gel 3 having a uniform thickness can be formed on the surface of the substrate 9 as shown in FIG. 3(C). The conductive substrate may be a one-side electrode substrate obtained by forming an electrode pattern on the surface of an insulating substrate. When a single-side electrode substrate is used, the electrodes can be formed in a comb shape, and both the anode and the cathode can be arranged on the substrate side. As a result, even non-conductive semiconductors and insulating objects can be favorably attracted without providing wiring or the like.

Next, in the method for manufacturing the electric adhesive sheet 1, the template 13 (see FIG. 3(D)) is arranged at a position facing the surface of the ER gel 3 in step S3. As shown in FIG. 3(D), the template 13 has a plurality of electrodes 15 on one surface thereof corresponding to the positions of the pillars 7 to be formed. Then, in step S3, the surface of the template 13 on which the electrode 15 is formed faces the surface of the ER gel 3, and the tip of the electrode 15 is positioned at a predetermined distance, for example, 10 to 20 μm, from the ER gel 3. Position the template 13 relative to the ER gel 3 so that it is spaced apart by .

Next, in the method for manufacturing the electric adhesive sheet 1, a voltage is applied between the template 13 and the conductive substrate 9 in step S4. The voltage applied at this time can be appropriately set according to the physical properties of the ER gel 3 and the physical shape of the pillars 7 to be formed. Then, as shown in FIG. 3(E), when the template 13 is connected to the power supply V, the substrate 9 is grounded, and a voltage is applied between the template 13 and the substrate 9, the ER gel is formed by the principle of electrostatic induction lithography described above. 3 begins to rise toward electrode 15 . Then, when a voltage is applied for a predetermined period of time, the protruding ER gel 3 takes the form of pillars 7 . The voltage during pillar formation and the distance between the template and the substrate are not limited to the ranges described above and can be adjusted as appropriate.

Next, in the method for manufacturing the electric adhesive sheet 1, the ER gel 3 having the shape of the pillars 7 is cured in step S5. As a method for curing the ER gel 3 having the shape of the pillar 7, a method of irradiating the ER gel 3 with ultraviolet rays, curing by heat, or natural curing can be used. Then, the step of curing the ER gel 3 in step S5 may be performed after stopping the voltage application in step S4, or may be performed in parallel with the voltage application in step S4. According to experiments by the inventors, the hardening step in step S5 was performed in parallel with the voltage application in step S4 because more regular pillars 7 could be formed. It is desirable to start the UV irradiation in step S5 before stopping.

Then, when the ER gel 3 is cured by irradiating the ER gel 3 with UV for a predetermined time, for example, 30 seconds to 45 seconds, the electric adhesive sheet 1 as shown in FIG. 3(F) can be produced.

As described above, the electric adhesive sheet 1 has a plurality of pillars 7 formed of the ER gel 3, so that the tops of the pillars 7 can be brought into contact with the article to be adhered. By bringing a plurality of pillars 7 into contact with an article at the same time to adhere and hold the article, for example, even if the adhesive strength of one pillar 7 is low, the article can be adhesively held by the adhesive strength of the other pillars 7 . As a result, even when the dispersibility of the ER particles 5 is low, the electrical adhesive sheet 1 as a whole can exert a stable adhesive force.

Examples of the present invention will be described in detail below.

(Example)
In Example 1, a template was prepared in which the size of each electrode was 100 μm×100 μm, and the spacing between the electrodes was 300 μm in the X direction and 300 μm in the Y direction.
Also, dimethylpolysiloxane was prepared as an ER gel, and 30% by weight of ER particles were mixed therein to prepare an ER gel. The ER particles used were acrylic polymer particles with semiconducting tin oxide attached to their surfaces, and had an average diameter of 16 μm.

Then, the prepared ER gel was applied onto a glass electrode substrate and leveled to a thickness of 70 μm to form an ER gel layer. Further, the template was fixed so that the tip of the electrode was positioned 170 μm away from the surface of the glass electrode substrate on which the ER gel layer was formed.

A plurality of specimens set in this manner were prepared, and voltages of 500 V, 600 V, and 700 V were applied to each template and glass electrode substrate for a predetermined period of time to produce three types of electrical adhesive sheets. All electroadhesive pillars were formed according to the shape of the template, keeping a distance of 300 μm between the pillars.

Then, the holding power of the electric pressure-sensitive adhesive sheet thus produced was measured. When measuring the holding force, the glass electrode substrate and the electrical adhesive sheet were fixed on a flat surface, and another glass electrode substrate was placed thereon. A strain gauge type force sensor was connected to an electrode to be held, and the fixing force generated was measured by sliding the electrode through the force sensor.

(Comparative example)
In the comparative example, electroadhesion was performed under the same conditions as in the example, except that a template was prepared in which the size of each electrode was 100 μm×100 μm, and the spacing between the electrodes was 100 μm in the X direction and 100 μm in the Y direction. A sheet was formed.

(Test results)
FIG. 4 is a graph showing the relationship between voltage application time (s) and voltage (V) when forming the electric pressure-sensitive adhesive sheets according to Examples and Comparative Examples, and FIG. A magnified photograph of the surface is shown. In FIG. 4, T1 indicates the time from the start of voltage application until the formation of the _first pillar, and _Tw indicates the time from the start of voltage application until all pillars are formed. "100-100" indicates the measurement result when using the template prepared in the comparative example, and "100-300" indicates the measurement result when using the template prepared in the example. In the template prepared in the comparative example, although the time T1 until the first pillars were formed could be measured, the pillars were not formed regularly, so it was not possible to determine whether all the pillars were formed. and could not measure the time Tw.

According to the results shown in FIG. 4, it can be seen that the higher the applied voltage, the shorter the time _T1 and the time _Tw , shortening the time to complete the pillar.

FIG. 6 is a graph showing the relationship between the holding power (holding power per unit area) of the electric adhesive sheet and the voltage. According to the results shown in FIG. 6, it can be seen that the holding force increases in proportion to the applied voltage. In particular, when a voltage of 600 V was applied, a holding force of 8.2 kPa per unit area was measured.

1 Electrical Adhesive Sheet 3 ER Gel 5 ER Particles 7 Pillar 9 Conductive Substrate 11 Layer of ER Gel 13 Template 15 Electrode

Claims (2)

An electric adhesive sheet using ER gel containing ER particles,
A bottom portion is integrally formed on the adhesive side surface of the electric adhesive sheet, and a plurality of pillars protruding from the bottom portion are formed of ER gel containing ER particles ,
The electrical adhesive sheet, wherein the top surfaces of the plurality of pillars exhibit adhesive force in response to voltage application . A method for producing an electrical pressure-sensitive adhesive sheet using an ER gel containing ER particles,
forming a layer of ER gel containing ER particles on a conductive substrate;
placing a template with a plurality of electrodes at a position facing the surface of the ER gel layer;
applying a voltage to the electrodes to lift the ER gel from the layer of ER gel;
curing the raised ER gel;
A method for producing an electric adhesive sheet.

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