JP2005245157A - Electrostatic attraction device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic attraction device equipped with a means for readily complying with countermeasures against deterioration to the aging of an attractive layer of the electrostatic attraction device, easily removing substances polluting the surface of the device, and easily repairing the stains and scratches on the attraction layer caused due to use over time. <P>SOLUTION: The electrostatic attraction device includes at least one pair of positive or negative laminar electrodes formed on a holding member; a power supply for providing the electrodes with a potential difference; and an attractive layer being a laminar dielectric material covering the electrodes, wherein a substance is attracted on the attracting layer surface by the electrostatic attraction force caused by polarized charges induced by the attracting layer, the attracting layer being laminar and detachable in the whole area or in the surface layer thereof. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

    The present invention relates to an electrostatic adsorption device that adsorbs an object by electrostatic Coulomb force.

  A so-called electrostatic adsorption device that adsorbs an object by electrostatic coulomb force has a wide range of industrial applications because it does not select an adsorption object unlike magnetic adsorption. For example, an electrostatic adsorption device (see Patent Document 1) for holding a silicon wafer in a vacuum evaporation apparatus, an apparatus using an electrostatic adsorption device as a paper turning mechanism in a copy machine (see Patent Document 2), and a sheet attached An electronic blackboard (see Patent Document 3) having an electrostatic adsorption device is disclosed as a means for achieving this.

As is well known, electrostatic adsorption is induced by an object in an electric field, with a reverse polarity charge due to electrostatic induction (in the case of a conductor) or a reverse polarity polarization charge due to polarization (in the case of an insulator), This is an apparatus for adsorbing an object in the direction of an electrode by an attractive force due to a Coulomb force between an electric field forming an electrode or an electric charge on an adsorption layer.
As a method of generating an electric field, there are a method of applying a potential difference (applying a voltage) to an electrode pair and a method of using spontaneous polarization (electric stone) of a ferroelectric material, but the former is generally used.

The electrostatic adsorption device can exert an adsorption force regardless of whether the object is a conductor or an insulator. However, when the object to be adsorbed is a conductor, if the electrode pair is exposed, it will be difficult to form an adsorption electric field as a result of a short circuit with the electrode pair, and an excessive current will flow through the adsorbent and damage the adsorbate. There was a fear. Therefore, in the electrostatic adsorption device described in Patent Document 1, the volume resistance of the electrode pair is devised to be 1 × 10 ⁹ to 10 × 10 ¹¹ Ω-cm to prevent an excessive current from flowing through the adsorbate. It is out.
Even if the electrode pair is exposed, if the object to be adsorbed is an insulator, there is no inconvenience that the electrode pair is short-circuited by the adsorbent, but generally the potential difference between the electrode pair requires several hundred to several thousand volts. The exposure of the electrode pair has a risk of electric shock, and discharge due to moisture, dust or the like may cause the adsorption operation to be incomplete. Therefore, it is necessary to cover the surface of the electrode pair.

In order to avoid inconvenience due to the exposure of the electrode pair, the electrostatic adsorption device described in Patent Document 3 or Patent Document 4 has a structure in which an adsorption layer that covers the surface of the electrode pair with a thin dielectric film is installed. Even if the electrode pair is changed to such a structure, the distance between the electrode pair and the adsorbate is increased by the thickness of the dielectric film, so that the adsorption force is slightly reduced, but polarization charges are still induced on the adsorption layer. Since the electrostatic induction charge or the polarization charge having the opposite sign to the polarization charge can be generated on the adsorption object, the adsorption operation can be performed without any trouble.
In this way, by covering the electrode pair with an adsorption layer made of a thin dielectric film, the problem caused by the exposed electrode pair is solved, there is no risk of electric shock, and the conductor and the insulator are adsorbed without distinction. An electrostatic chuck that can be used is realized.

However, on the other hand, when the electrode pair is covered with the adsorption layer, the ions adsorbed on the adsorption layer surface, the generated triboelectric charges, etc. remain as they are, and the phenomenon of reducing the adsorption force occurs. It is preferable that ions and charges trapped on the surface of the adsorption layer can be easily discharged to the electrode pair.
Furthermore, since the adsorption layer is exposed to the electric field formed by the electrodes for a long period of time, it tends to cause deterioration in physical properties and contamination due to adsorption of dust, dust and the like.
Thus, it is preferable that the adsorption layer covering the electrode pair can simultaneously solve the problem of short circuit or electric shock during the adsorption of the conductor and the problem of retention of ions and charges on the adsorption layer surface, and further durability for long-term use. It is preferable that the problem of preventing contamination and dirt can be solved. Among the various problems described above, the inventors have already found and applied for a method for simultaneously solving the problem of short circuit and electric shock and the problem of retention of charge in the adsorption layer. An effective solution has not been found for the problem related to contamination prevention.

JP-A-5-315435 JP-A-5-2011175 JP-A-5-056201 JP-A-6-225556

As described above, since the electrostatic adsorption device adsorbs regardless of whether the object is a conductor or an insulator, dust, dust, and insects are easily attached to the surface. Although dirt can be wiped off, it may be difficult to wipe off by applying a continuous electric field, and it can be pointed out that the operation of wiping off the dirt itself is uncomfortable or scatters contaminants. Furthermore, according to the conventional electrostatic adsorption device, characteristic deterioration during continuous energization is usually unavoidable. That is, the object of the present invention is to easily cope with the deterioration of the adsorption layer of the electrostatic adsorption device over time, and It is an object of the present invention to provide a means for easily removing substances that contaminate the surface of the adsorption device and easily repairing dirt and scratches on the adsorption layer over time.

Conventionally, the adsorbing layer that needs to have these functions has been fixed by an adhesive or the like so as to be integrated with the electrode or the holding surface. However, as a result of repeated research, the present inventors do not need the adhesive layer to be firmly bonded to the electrode or the holder, and the strength of the temporary fixing so that the electrode surface does not float due to the inclusion of air or the like. It was found that the adsorbing layer itself can be adsorbed to the electrode by electrostatic force and can be sufficiently fixed if it is uniformly adhered. Furthermore, the present inventors have found that the above problem can be solved by providing a removable layer having electrostatic adsorption suitability on the uppermost layer of the adsorption layer of the electrostatic adsorption device, and have reached the present invention.
That is, the present invention comprises at least a pair of positive and negative layered electrodes formed on a holding material, a power source for applying a potential difference to the electrodes, and an adsorption layer that is a layered dielectric covering the electrodes, An electrostatic adsorption device that adsorbs an object on the surface of the adsorption layer by electrostatic attraction caused by polarization charges induced in the electrode, wherein the adsorption layer is detachable in its entirety or in its surface layer portion. An electrostatic adsorption device is provided.
Since the adsorption layer used in the present invention can be entirely or detachably attached to the surface layer portion, the adsorption layer can be appropriately replaced during a long-term use, and the adsorption layer may be contaminated with dust or dust. It can be replaced before physical properties such as insulation resistance are lowered by applying a long-term electric field.

  In the electrostatic adsorption device of the present invention, by making the adsorption layer itself detachable or by making the surface layer part of the adsorption layer detachable, the layer deteriorated with time can be exchanged, and the entire electrostatic adsorption device can be replaced. The life can be extended. In addition, even when contaminants adhere to the surface of the electrostatic adsorption device, it is possible to remove dirt by exchanging the entire adsorption layer or the surface layer portion of the adsorption layer. By adding such a function, for example, when the electrostatic adsorption device of the present invention is used for the purpose of adsorbing and removing contaminants such as indoor dust and dust, insects, etc. The removed material can be easily discarded and cleaned.

  FIG. 1 shows a cross-sectional view of a conventional electrostatic attraction apparatus viewed from the side. 1 and 2 are electrode pairs. There may be a plurality of electrode pairs, and the planar configuration is preferably a comb-shaped electrode in order to improve the adsorption function. 3 is an adsorption layer covering the electrode pair, 4 is an adhesive layer, 5 is an electrode holding material, and a voltage is applied to the electrodes 1 and 2 by a power source 6. An electric field is generated between the electrodes 1 and 2 due to the potential difference applied between the electrodes 1 and 2. The electric field is expressed by electric lines of force 7. A part of the electric lines of force passes through the adsorption layer 3, induces a polarization charge in the adsorption layer, and further approaches the adjacent object 8 by electrostatic induction or polarization. A charge opposite to the charge is generated, and the object is adsorbed on the surface of the adsorption layer 3 by Coulomb force. The above is the structure of the electrostatic adsorption device and the principle of adsorption. Note that the adhesive layer 4 is omitted when the entire adsorbing layer is removable, or is replaced with a lightly peelable adhesive layer.

In the electrostatic adsorption device having the above-described configuration and operation principle, the adsorption layer used in the present invention can be entirely or detachably attached. These removable adsorption layers have an adhesive layer portion on one surface, and may be fixed by the adhesive force of the adhesive layer portion (see FIGS. 3 and 5) or on the electrode. It may be fixed without the adhesive layer by the electrostatic attractive force of the dielectric polarization charge induced on the adsorption layer by the charge of the electrode or the charge on the electrode (see FIGS. 2 and 4).
If it is possible to divide the adsorption layer into a surface layer portion and a lower layer portion, as in the case where the surface layer portion of the adsorption layer is detachable, the electrode at the time of adsorbing the conductor in the function of the adsorption layer. The functions of insulation and safety for preventing electric shock are achieved by the lower layer portion, and the surface layer portion only needs to be protected from the contaminants attracted by the Coulomb force. That is, even if the lower layer portion is fixed to the surface of the electrode or the holding material, it is sufficient that the surface layer portion is in close contact with the lower layer portion, and conversely, the surface layer is always new because it is removable. This is preferable because the state can be maintained and the life of the entire electrostatic adsorption device can be extended.
In addition, since only the surface layer is removable, it is possible to easily remove contaminants etc. along with the surface layer when unpleasant contaminants adhere, and to restore the deteriorated adsorption layer to its original new state. I can do it.
The adsorption layer used in the present invention is a dielectric that stably generates polarization charges due to dielectric polarization without short-circuiting between electrode pairs even when the adherend is a conductor. Further, as described above, since the potential difference between the electrode pairs is usually applied several hundred to several thousand volts, it is preferable to have sufficient insulation performance with the used film thickness and prevent electric shock of the user.

As the adsorption layer of the adsorption device of the present invention, polyester, polyurethane, polyvinyl chloride, polyvinylidene chloride, nylon, acrylic, polycarbonate, polyacetal, phenol, epoxy and other plastics, ethylene vinyl alcohol copolymer resin, polyvinyl alcohol, etc. A mixed plastic plate or sheet in which two or more of these are mixed, or a material in which the same or different types of plates or sheets are laminated is used. Usually, the adsorption layer is set to a volume resistance of 1 × 10 ¹¹ Ωcm or more in order to eliminate leakage between electrode pairs. If the volume resistivity is less than 1 × 10 ¹¹ , charge leaks through the adsorption layer, the electrode voltage does not increase, and the adsorption force tends to be insufficient. Also, the power consumption due to the leakage current occurs, resulting in efficiency. Tend to get worse.

On the other hand, in these electrostatic adsorption devices, free charges attached to the adsorption layer due to friction of the adsorption layer or the like are not discharged to the electrodes, and there is a tendency to reduce the magnitude of the potential of the adsorption layer and reduce the adsorption force. In order to discharge the free charge to the electrode pair in a short time, it is preferably set in the range of 1.0 × 10 ^{11 to} 1.0 × 10 ¹⁵ Ωcm. In order to set such a volume resistance range, the above-mentioned plastics are modified by various known conductive methods, or conductive materials (conductive fine powder, conductive plasticizer, conductive polymer, etc.) are added. May be performed.

  The thickness of the adsorption layer can be appropriately set between 1 μm and 1 mm, depending on the voltage applied to the electrode of the electrostatic adsorption device and the assumed adsorption force. However, in order not to reduce the adsorption force due to the Coulomb force, 100 to 200 μm is preferable.

When the adsorption layer of the present invention has a removable surface layer portion, the surface layer portion of the adsorption layer must have the basic characteristics of the other lower layer adsorption layers, and the lower layer portion adsorption It is composed of the same material as the layer. Furthermore, the removable surface layer adsorption layer has text and design printing and various functions (for example, a coating agent for antifouling properties) as long as the electrostatic adsorption performance is not impaired. Coating for making it possible can be performed by a well-known method.
The adsorption layer of the surface layer portion may be fixed to the adsorption layer of the lower layer portion by the electrostatic attraction of the polarization charge induced on the surface of the adsorption layer by the charge on the electrode. As a temporary improvement to the lower layer when the power is turned off or when the power is cut off, it may be adhered with an adhesive strength of light peeling.

For adhesion, the adsorbing layer itself is, for example, an elastomer, and due to this, an adhering force may be exerted between the adsorbing layer and other layers, or between the adsorbing layers. An adhesive may be applied to the contact surfaces of the layers or the adsorbing layers so as to have adhesiveness. As the adhesive force at that time, the peeling speed, 300 mm / min. When measured against a 180 ° peel, stainless steel plate, it is preferably 1.5 N or less per 1 cm width. If the strength is higher than this, it is difficult to remove the adsorptive layer when it is peeled off. Since the adhesive strength is only temporarily fixed, it can be defined by the workability when peeling from the lower layer, and when used at a width of 0.5 N or less, for example, 1 m width, the adhesive strength is 50 N or less. More preferably.
These adhesives include rubber adhesives, acrylic adhesives, urethane adhesives, silicon adhesives, etc., but are not particularly limited.
When the electrostatic chuck is used for a long time with the power on, the attachment and detachment of the detachable surface layer portion may be performed exclusively by the electrostatic attraction of the electrostatic chuck itself. At this time, a voltage is previously applied to the electrodes of the electrostatic adsorption device, and a new adsorption layer is attached to the surface layer portion.
Although the film thickness of the adsorption layer of the removable surface layer part is not specifically limited, it can be appropriately set between 1 μm and 1 mm as in other parts of the adsorption layer. 10 to 200 μm is preferable when the adsorption force due to the Coulomb force is not reduced and the ease of peeling is taken into consideration.

  The electrode of the electrostatic attraction apparatus of the present invention is formed in layers on the holding material 5. The electrode can be formed by metal deposition or applying a conductive paint containing metal powder or carbon powder on the holding material, or can be formed on the holding material by a transfer process. Alternatively, the electrode metal foil may be fixed on the holding material with an insulating adhesive, or may be formed by being pressed and embedded in the holding material. There may be a plurality of layered electrode pairs 1 and 2 of the electrostatic adsorption device of the present invention, and the configuration on the plane can use, for example, a comb-shaped plane pattern in order to increase the adsorption efficiency. When a thin sheet-like material is used as the holding material, the electrodes can be formed on both sides of the holding material.

The holding material is an insulative support for forming electrodes in a laminated form on the holding material, and a shape suitable for the end use such as a block, a plate, or a sheet can be selected. In view of the properties, an insulating holding film is preferable because of its wide applicable range. In general, it is preferable to use an insulating holding film having a volume resistivity of 10 ¹⁴ Ωcm or more, and the thickness of the insulating holding material is preferably 20 μm or more from the viewpoint of insulation against an applied voltage. Further, the insulating holding film can be made of the same material as the adsorption layer.

In the electrostatic adsorption device of the present invention, the surface of the electrode is covered with the adsorption layer, but in order to make the insulation of the electrode more complete, it is preferable to fill the space between the electrode and the adsorption layer with an insulating adhesive. . By doing in this way, electrical insulation and fixation of an adsorption layer can be performed more reliably. The insulating adhesive preferably has a volume resistivity of 10 ¹³ Ωcm or more. When making the entire adsorption layer detachable, the adhesive layer should not be provided, or even if it is provided, an adhesive layer that can maintain light peeling instead of the adhesive layer is used to insulate the electrode and the adsorption layer. Fix it.

Hereinafter, each component will be described in more detail with reference to examples.

Hereinafter, an adhesive sheet was produced as a material in order to configure the electrostatic adsorption device of the example.
(Adhesive film 1)
A two-part curable acrylic pressure-sensitive adhesive (Dickplast PSX-102D: manufactured by DIC) is coated and dried to a thickness of 30 μm (dry) on a release-treated PET film that has been subjected to silicon treatment. A polyvinyl chloride resin film having a resistivity of 3.7 × 10 ¹³ Ωcm (manufactured by Riken Technos) was attached, and the release PET film was peeled off to produce a vinyl chloride adhesive film.
The adhesive strength of this adhesive film to the SUS plate was 5.5 N / 10 mm (based on JIS C2107, peeling speed 300 mm / min. 180 ° peeling).

(Adhesive film 2)
A polyester adhesive processed film was prepared by processing in the same manner as the adhesive film 1 except that a polyester polyether elastomer (manufactured by Teijin Kasei) having a thickness of 100 μm and a volume resistivity of 9.4 × 10 ¹⁴ Ωcm was used as the film. .
The adhesive strength of the adhesive film to the SUS plate was 4.7 N / 10 mm (based on JIS C2107, peeling speed 300 mm / min. 180 ° peeling).

(Adhesive film 3)
A two-part curable acrylic pressure-sensitive adhesive (AS-409: manufactured by Yushi Co., Ltd.) is applied and dried to a siliconized release PET film with a thickness of 15 μm (dry). A polyvinyl chloride resin film having a resistivity of 3.7 × 10 ¹³ Ωcm (manufactured by Riken Technos Co., Ltd.) was used for bonding, and the release PET was peeled off to produce a vinyl chloride adhesive processed film.
The adhesive strength of the adhesive film to the SUS plate was 0.8 N / 10 mm (based on JIS C2107, peeling rate 300 mm / min. 180 ° peeling).

(Adhesive film 4)
A two-part curable urethane-based pressure-sensitive adhesive (Vainsol U-250: manufactured by Yushi Co., Ltd.) is applied and dried to a siliconized release PET film at a thickness of 15 μm (dry), and a film having a thickness of 100 μm, A polyvinyl chloride resin film (manufactured by Riken Technos Co., Ltd.) having a volume resistivity of 3.7 × 10 ¹³ Ωcm was attached, and the release PET was peeled off to produce a vinyl chloride adhesive film.
The adhesive strength of the adhesive film to the SUS plate was 0.2 N / 10 mm (based on JIS C2107, peeling rate 300 mm / min. 180 ° peeling).

(Adhesive film 5)
A polyester adhesive processed film was produced by processing in the same manner as the adhesive film 4 except that a polyester polyether elastomer (manufactured by Teijin Kasei) having a thickness of 100 μm and a volume resistivity of 9.4 × 10 ¹⁴ Ωcm was used as the film. .
The adhesive strength of the adhesive film to the SUS plate was 0.2 N / 10 mm (based on JIS C2107, peeling rate 300 mm / min. 180 ° peeling).

(Example 1)
An electrode pattern was formed by silk printing with a conductive carbon ink (volume resistivity: 10 Ωcm) on a biaxially stretched polyester film (manufactured by Toray) having a thickness of 100 μm and a volume resistivity of 1.2 × 10 ¹⁶ Ωcm as a holding material. On the polyester film on which pattern printing was carried out, the vinyl chloride adhesive processing film produced with the said adhesive film 1 was bonded together as an adsorption layer. Furthermore, the electrostatic adsorption sheet | seat of FIG. 5 was produced by bonding the vinyl chloride adhesion processing film produced with the said adhesive film 3 on the upper surface of this adsorption layer.

(Example 2)
An electrode pattern was formed by silk printing with a conductive carbon ink (volume resistivity: 10 Ωcm) on a biaxially stretched polyester film (manufactured by Toray) having a thickness of 100 μm and a volume resistivity of 1.2 × 10 ¹⁶ Ωcm as a holding material. On the polyester film on which pattern printing was carried out, the electrostatic adsorption sheet was produced by bonding together the vinyl chloride adhesion processing film produced with the said adhesion film 1 as an adsorption layer.
Further, while energizing the electrostatic adsorption sheet, a polyvinyl chloride resin film (manufactured by Riken Technos) having a thickness of 100 μm and a volume resistivity of 3.7 × 10 ¹³ Ωcm is bonded to the upper surface of the adsorption layer. The electrostatic adsorption sheet of FIG. 4 was produced.

(Example 3)
As the pressure-sensitive adhesive film to be bonded on the adsorption layer, the same process as in Example 1 was performed except that the vinyl chloride pressure-sensitive adhesive film produced with the pressure-sensitive adhesive film 4 was used, and the electrostatic adsorption sheet of FIG. 5 was produced.

Example 4
An electrode pattern was formed by silk printing with a conductive carbon ink (volume resistivity: 10 Ωcm) on a biaxially stretched polyester film (manufactured by Toray) having a thickness of 100 μm and a volume resistivity of 1.2 × 10 ¹⁶ Ωcm as a holding material. On the polyester film on which pattern printing was carried out, the polyester adhesive processing film produced with the said adhesive film 2 as an adsorption layer was bonded together. Furthermore, the electrostatic adsorption sheet | seat of FIG. 5 was produced by bonding the vinyl chloride adhesion processing film produced with the said adhesive film 3 on the upper surface of this adsorption layer.

(Example 5)
An electrode pattern was formed by silk printing with a conductive carbon ink (volume resistivity: 10 Ωcm) on a biaxially stretched polyester film (manufactured by Toray) having a thickness of 100 μm and a volume resistivity of 1.2 × 10 ¹⁶ Ωcm as a holding material. On the polyester film on which the pattern was printed, an electrostatic adsorption sheet was produced by laminating a polyester adhesive processed film produced by the adhesive film 2 as an adsorption layer.
Further, while energizing the electrostatic adsorption sheet, a polyvinyl chloride resin film (manufactured by Riken Technos) having a thickness of 100 μm and a volume resistivity of 3.7 × 10 ¹³ Ωcm is bonded to the upper surface of the adsorption layer. The electrostatic adsorption sheet of FIG. 4 was produced.

(Example 6)
The same processing as in Example 5 was performed except that a polyester polyether elastomer (manufactured by Teijin Kasei) having a thickness of 100 μm and a volume resistivity of 9.4 × 10 ¹⁴ Ωcm was used as a film to be bonded onto the adsorption layer. An electrostatic adsorption sheet was prepared.

(Example 7)
An electrode pattern was formed by silk printing with a conductive carbon ink (volume resistivity: 10 Ωcm) on a biaxially stretched polyester film (manufactured by Toray) having a thickness of 100 μm and a volume resistivity of 1.2 × 10 ¹⁶ Ωcm as a holding material. The polyester adhesive processing film produced by the said adhesive film 5 was bonded together on the polyester film by which the pattern printing was carried out, and the electrostatic adsorption sheet of FIG. 3 was produced.

(Comparative Example 1)
An electrode pattern was formed by silk printing with a conductive carbon ink (volume resistivity: 10 Ωcm) on a biaxially stretched polyester film (manufactured by Toray) having a thickness of 100 μm and a volume resistivity of 1.2 × 10 ¹⁶ Ωcm as a holding material. The conventional type electrostatic adsorption sheet of FIG. 1 was produced by laminating a vinyl chloride adhesive processed film produced by the adhesive film 1 as an adsorbing layer on the patterned polyester film.

The electrostatic adsorption sheet produced as described above was incorporated into an electrostatic adsorption apparatus and evaluated by the following test method.
(Evaluation test)
(A) When the apparatus is turned on, a potential of 1500 V is applied to the electrodes 1 and 2 and an aluminum plate is attached as an adherend to the adsorption surface of the apparatus.
(B) In this state, store under accelerated conditions of 40 ° C. to 80% and observe over time.
(C) After 1 month, test the following evaluation items.
(D) After the evaluation of (c), in the continuation test, the removal layer is removed from the embodiment and replaced with a new removal layer to continue the test. The comparative example is continuously tested as it is.
(E) After 2 months, evaluate the following items.

(Evaluation items and methods)
(1) Removal Layer Appearance For Example 1-7, change in the appearance (discoloration) of the surface of the removal layer after removing the aluminum of the adherend is observed. The following evaluation was performed.
◎ No change
○ Slight discoloration but almost no discoloration.
△ faintly discolored
× Clearly discolored.

(2) Adsorption layer appearance (a) About Example 1-6, the change of the external appearance (discoloration) of the coating surface after peeling a removal layer was observed on the following references | standards.
◎ No change
○ Slight discoloration but almost no discoloration.
△ faintly discolored
× Clearly discolored.
(B) About the comparative example, the change of the external appearance (discoloration) of the removal layer surface of the trace which removed the aluminum of the to-be-adhered body was observed on the following references | standards.
◎ No change
○ Slight discoloration but almost no discoloration.
△ faintly discolored
× Clearly discolored.

(3) Peelability In the examples, the resistance at the time of peeling from the lower surface of the removal layer is compared.

(4) Surface wiping property The portion of the adsorbent layer surface (which means the adsorbed layer surface to be removed in the examples and the adsorbed layer surface in the comparative example) where the adherend is not placed is covered. Since there is no air, dust in the air is adsorbed and contaminated. The surface of the adsorbing layer with the dirt adhered was wiped with a cloth moistened with water, and the ease of wiping off the dirt was comparatively observed according to the following criteria.
◎ Return to the original.
○ Almost return to the original.
△ Some traces remain.
× Black marks remain.

(5) Volume resistance Volume resistance is measured about each film of material.

  Hereinafter, the types, shapes, coating thicknesses, etc. of the raw materials used to produce the adsorption sheets for Examples and Comparative Examples, and the evaluation results are as shown in the table.

As is clear from the results in the table, the removed layer portions of Examples 1 to 7 can be peeled off from the lower surface without any problems even after 1 month of 40 ° C. to 80%. After the removal layer is removed, the appearance of the adsorbing layer does not cause discoloration of PVC or polyester, and maintains the initial appearance. This was the same even after 2 months of aging at 40 ° C.-80%. On the other hand, in the comparative example, after one month, the appearance of the PVC has started to change slightly, and after two months, it has turned pink. As described above, the entire adsorption layer (Example 7) or the surface layer portion of the adsorption layer according to the present invention is configured to be detachable (Examples 1 to 6). Discoloration can be repaired and the life of the electrostatic adsorption sheet can be extended.
In addition, the polyester polyether elastomer film used in this example is less susceptible to discoloration than PVC and has excellent contamination, and is suitable as an adsorption layer for an electrostatic adsorption sheet.

1 is a schematic view of a conventional electrostatic adsorption device. It is the schematic which shows an example of the electrostatic adsorption apparatus of this invention which has the adsorption | suction layer which can be attached or detached entirely, and does not have an adhesive layer. It is the schematic which shows an example of the electrostatic adsorption apparatus of this invention which has the adsorption layer which the whole can attach or detach, and has an adhesive layer. It is the schematic which shows an example of the electrostatic adsorption apparatus of this invention which has an adsorption layer in which a surface layer part is removable, and does not have an adhesive layer. It is the schematic which shows an example of the electrostatic adsorption apparatus of this invention which has an adsorption layer in which a surface layer part is removable, and has an adhesive layer.

Explanation of symbols

1, 2 electrode pairs
3 Adsorption layer (lower layer part)
4 Adhesive layer
5 Holding material
6 Power supply 7 Electric field lines 8 Object to be adsorbed 9 Detachable adsorption layer (surface layer part)
10 Adhesive layer

Claims (4)

Polarization induced by the adsorption layer, comprising at least a pair of positive and negative electrode layers formed on the holding material, a power source for applying a potential difference to the electrodes, and an adsorption layer that is a layered dielectric covering the electrode. In the electrostatic adsorption device for adsorbing an object on the surface of the adsorption layer by electrostatic attraction due to electric charge, the adsorption layer is detachable in its entirety or in its surface layer part in a layered manner. The electrostatic adsorption device according to claim 1, wherein the detachable adsorption layer or a surface layer portion of the adsorption layer is fixed via an adhesive layer. The electrostatic adsorption according to claim 1, wherein the removable adsorption layer or a surface layer portion of the adsorption layer is fixed by an electrostatic attraction caused by a charge on the electrode or a polarization charge induced in the adsorption layer by the electrode. apparatus. The electrostatic adsorption device according to claim 1, wherein the removable adsorption layer is a polyester polyether elastomer.

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