JP5210078B2 - Electrically peelable pressure-sensitive adhesive composition, electrically peelable adhesive product, and method for peeling - Google Patents

Description

  The present invention relates to an electric peelable pressure-sensitive adhesive composition, an electric peelable pressure-sensitive adhesive product, and a peeling method thereof. More specifically, the present invention relates to an electro-releasable pressure-sensitive adhesive composition, an electro-releasable pressure-sensitive adhesive product that can be easily peeled from an adherend, and a method for peeling the same. .

  Removable adhesive tapes are used in various applications (for example, surface protective films, coating masking tapes, removable notes, etc.). This pressure-sensitive adhesive tape generally comprises a base material and a pressure-sensitive adhesive layer laminated thereon. The adhesive layer is required to have removability as well as adhesiveness. That is, when transporting, storing, and processing the adherend, there is a demand for adhesiveness that does not peel from the adherend and removability that can be easily removed after performing the function.

For example, a method described in, for example, WO 2007/018239 (Patent Document 1) has been proposed as a method for realizing the contradictory properties of the adhesiveness and the removability.
In WO2007 / 018239, it is described that an adhesive that can be peeled off when a voltage is applied can be provided by using an ionic liquid as an adhesive. In this publication, an ionic liquid is a molten salt that is liquid at room temperature, has no vapor pressure, and has properties such as high heat resistance, nonflammability, and high chemical stability.
WO2007 / 018239

  The above publication is about an electro-releasable adhesive composition, and development of an electro-releasable pressure-sensitive adhesive having a high bonding effect has been desired from the moment of application.

Thus, according to the present invention, an acrylic polymer, an ionic liquid exhibiting an ionic conductivity of 10 ⁻⁴ to 10 ⁻² S / cm, and polyethylene glycol, the ionic liquid and polyethylene glycol, An electropeelable pressure-sensitive adhesive composition is provided that is contained in an amount of 1 to 40 parts by weight with respect to 100 parts by weight of an acrylic polymer.
Moreover, according to this invention, it has an electroconductive support body and the electrically peelable adhesive layer formed on it, and the said electrically peelable adhesive layer contains the said electrically peelable adhesive composition. An electrically peelable adhesive product is provided.

  Furthermore, according to the present invention, after the above-described electro-releasable pressure-sensitive adhesive product is attached to an adherend so that the electro-releasable pressure-sensitive adhesive layer faces, a voltage is applied to the electro-releasable pressure-sensitive adhesive layer. Thus, there is provided a method for peeling the electro-peelable adhesive product, wherein the electro-peelable adhesive product is peeled from the adherend.

  ADVANTAGE OF THE INVENTION According to this invention, the electrically peelable adhesive composition which can form the adhesive layer which can be peeled without applying a voltage for a short time by applying a voltage can be provided.

The electroreleasable pressure-sensitive adhesive composition of the present invention (hereinafter simply referred to as a pressure-sensitive adhesive composition) contains an acrylic polymer, an ionic liquid, and polyethylene glycol.
(Acrylic polymer)
The acrylic polymer can be obtained by polymerizing an acrylic monomer optionally in the presence of a polymerization initiator. As the acrylic polymer, any polymer can be used as long as it can at least adhere to the adherend. Usually, from the viewpoint of tackiness, a polymer having a weight average molecular weight in the range of 10,000 to 5,000,000 is used as the acrylic polymer.
The weight average molecular weight means a value calculated using a GPC System 21 manufactured by Shodex and assuming the mobile phase as tetrahydrofuran. This value is a weight average molecular weight in terms of polystyrene.

(1) Acrylic monomer The acrylic monomer preferably contains an alkyl (meth) acrylate having an alkyl group having 1 to 10 carbon atoms as a main component (50% by weight or more). In addition, (meth) acrylate means a methacrylate or an acrylate.

  Examples of the alkyl (meth) acrylate having an alkyl group having 1 to 14 carbon atoms include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl ( (Meth) acrylate, sec-butyl (meth) acrylate, t-butyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isononyl (meth) acrylate, dodecyl ( And (meth) acrylate. These alkyl (meth) acrylates may be used alone or in combination of two or more. Among these alkyl (meth) acrylates, alkyl (meth) acrylates having an alkyl group having 1 to 8 carbon atoms are preferred, alkyl (meth) acrylates having an alkyl group having 1 to 4 carbon atoms are more preferred, and n-butyl ( (Meth) acrylate is more preferred, and n-butyl acrylate is particularly preferred.

  Other acrylic monomers include carboxyl group-containing monomers such as acrylic acid, methacrylic acid, carboxyethyl acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate And hydroxyl group-containing monomers such as 6-hydroxyhexyl (meth) acrylate and (4-hydroxymethylcyclohexyl) -methyl acrylate. These other (meth) acrylates may be used alone or in combination of two or more. The (meth) acrylate preferably contains both a carboxyl group-containing monomer and a hydroxyl group-containing monomer.

  The acrylic monomer contains an alkyl (meth) acrylate having an alkyl group having 1 to 10 carbon atoms as a main component. Therefore, the acrylic monomer may be composed only of alkyl (meth) acrylate without using any other acrylic monomer. Further, from the viewpoint of easily obtaining a pressure-sensitive adhesive composition having desired performance, other acrylic monomers are preferably contained in an amount of less than 50% by weight and 1% by weight or more, and contained in an amount of 5 to 30% by weight. More preferably, it is more preferably 5 to 15% by weight.

  Moreover, when both the carboxyl group-containing monomer and the hydroxyl group-containing monomer are included, the content of both is preferably in the range of 1 to 20 parts by weight when the total monomer amount is 100 parts by weight. Adhesive properties can be improved by using both monomers within this range. Furthermore, the range of 1 to 10 parts by weight is more preferable.

  Furthermore, you may add a vinyl-type monomer to (meth) acrylate as needed. Examples of vinyl monomers include itaconic acid, maleic acid, crotonic acid; maleic anhydride, itaconic anhydride, vinyl acetate, N-vinylpyrrolidone, N-vinylcarboxylic amides, styrene, N-vinylcaprolactam, and the like. It is done. These vinyl monomers may be used alone or in combination of two or more.

(2) Polymerization initiator As an optional polymerization initiator, for example, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylpropionamidine) disulfide, 2, 2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2-methylbutyronitrile), 1 , 1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis (2,4,4-trimethylpentane), dimethyl-2,2′-azobis (2-methylpropionate), 2, 2'-azobis [2-methyl-N- (phenylmethyl) -propionamidine] dihydrochloride, 2,2'-azobis [2- (3,4,5,6-tetrahydropyrimidin-2-yl) pro Azo-based polymerization initiators such as dihydrochloride and 2,2′-azobis [2- (2-imidazolin-2-yl) propane]; persulfate-based polymerization initiators such as potassium persulfate and ammonium persulfate; Benzoyl peroxide, hydrogen peroxide, t-butyl hydroperoxide, di-t-butyl peroxide, t-butyl peroxybenzoate, dicumyl peroxide, 1,1-bis (t-butylperoxy) -3, Start of peroxide polymerization such as 3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclododecane, 3,3,5-trimethylcyclohexanoyl peroxide, t-butylperoxypivalate Agents: Redox polymerization initiators composed of persulfate and sodium hydrogen sulfite. These polymerization initiators may be used alone or in combination of two or more.

  The polymerization initiator is preferably used in the range of 0.005 to 1 part by weight with respect to 100 parts by weight of the acrylic monomer. By using a polymerization initiator in this range, an acrylic polymer with improved adhesive properties can be formed.

(3) Other component As another component, the organic solvent may be contained from a viewpoint of the ease of use of the adhesive composition on a base | substrate. The organic solvent is not particularly limited, and examples thereof include known organic solvents that can be used for the pressure-sensitive adhesive composition. Examples thereof include aliphatic hydrocarbons such as hexane and heptane, esters such as methyl acetate, ethyl acetate, and propyl acetate, and aromatic hydrocarbons such as toluene, xylene, and ethylbenzene. These organic solvents may be used alone or in combination of two or more.
In addition, when using an organic solvent, it is preferable to adjust the use ratio so that the solid content content which consists of an acryl-type polymer may be 10 weight% or more. Moreover, it is preferable that the usage rate is prepared so that the solid content is 20 to 50% by weight.

(4) Viscosity The pressure-sensitive adhesive composition preferably has a viscosity of 1000 mPa · s or more when the solid content is 40% by weight. By having this viscosity, it is possible to ensure adhesiveness when no voltage is applied. A more preferable viscosity is 2000 to 10000 mPa · s.
The viscosity is a value measured by adjusting the temperature of the pressure-sensitive adhesive composition to 25 ° C., and then using a BH viscometer manufactured by Tokimec Co., Ltd. under a rotation speed of 10 rpm.

(Ionic liquid)
The ionic liquid is a molten salt that is liquid at room temperature (about 25 ° C.), and is also called a room temperature molten salt. In addition, the ionic liquid has characteristics such as no vapor pressure (nonvolatile), high heat resistance, nonflammability, and chemical stability.
In the ionic liquid, by applying a voltage, anions move to the anode side and cations move to the cathode side. The inventors consider that the redox reaction occurs at the interface between the electrode and the pressure-sensitive adhesive composition, whereby the adhesive strength of the pressure-sensitive adhesive composition becomes weak, and as a result, the peelability is improved.

The ionic liquid has an ionic conductivity of 10 ⁻⁴ to 10 ⁻² S / cm. By having an ionic conductivity in this range, it is possible to impart sufficient peelability to the pressure-sensitive adhesive composition by applying a voltage. More preferable ionic conductivity is 10 ⁻³ to 10 ⁻² S / cm. The measuring method of ionic conductivity is described in the column of an Example.
As the ionic liquid, for example, the following formula

(In the formula, R ¹ is a divalent hydrocarbon group having 2 to 8 carbon atoms which may contain a nitrogen atom constituting a ring together with the nitrogen atom, and R ² and R ³ are the same or different, and An atom or an alkyl group having 1 to 6 carbon atoms (provided that R ³ does not exist when a nitrogen atom forms a double bond with an adjacent carbon atom))
A cation represented by
Br ⁻ , AlCl ₄ ⁻ , Al ₂ Cl ₇ ⁻ , NO ₃ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , CH ₃ COO ⁻ , CF ₃ COO ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (CF ₃ SO ₂ ) ₃ C ⁻ , AsF ₆ ⁻ , SbF ₆ ⁻ , F (HF) _n ⁻ , CF ₃ (CF ₂ ) ₃ SO ₃ ⁻ , (CF ₃ CF ₂ SO ₂ ) ₂ N ⁻ and CF ₃ CF ₂ CF ₂ COO ^- salts with anion selected from.

In the above formula, a ring composed of R ¹ and a nitrogen atom includes a saturated alicyclic hydrocarbon such as cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclopropene, cyclobutene, cyclopentene, cyclohexene. , Cycloheptene, cyclooctene, cyclopentadiene, a ring in which at least one carbon atom constituting a hydrocarbon ring such as an unsaturated cyclic hydrocarbon such as benzene is replaced with a nitrogen atom is included.

Examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group. The alkyl group having 3 to 8 carbon atoms includes structural isomers.
Among the ionic liquids, a salt of a cation selected from a pyridinium cation, a cycloaliphatic ammonium cation and an imidazolium cation and an anion selected from (CF ₃ SO ₂ ) ₂ N ⁻ and BF ₄ ⁻ It is preferable that

  The ionic liquid can be obtained from Kanto Chemical Co., Ltd. and Guangei Chemical Industry (IL series). For example, 1-hexylpyridinium bis (trifluoromethanesulfonyl) imide, N-butyl-N-methylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-ethyl-3-methylimidazolium tetrafluoroborate is available from Kanto Chemical Yes, from Guangei Chemical Industry Co., Ltd., 1-ethyl-3-methylimidazolium hexafluorophosphate (IL-C3), 1-butylpyridinium tetrafluoroborate (IL-P10), 1-hexylpyridinium bis (trifluoromethanesulfonyl) Imide (IL-P14) is available.

(Polyethylene glycol)
The inventors consider that polyethylene glycol has a function as a migration accelerator that assists the migration of the ionic liquid when a voltage is applied. As this polyethylene glycol, what has an average molecular weight of 200-6000 can be used. By having an average molecular weight within this range, it is possible to impart sufficient peelability to the pressure-sensitive adhesive composition by applying a voltage. Polypropylene glycol is known as a similar glycol, but it has been confirmed that polypropylene glycol does not sufficiently reduce the adhesiveness of the pressure-sensitive adhesive composition when a voltage is applied, and is difficult to peel off. That is, the inventors have unexpectedly found that this phenomenon is unique to polyethylene glycol.

(Use ratio of acrylic polymer, ionic liquid, polyethylene glycol)
The ionic liquid and polyethylene glycol are used in the range of 1 to 40 parts by weight with respect to 100 parts by weight of the acrylic polymer. By using in this range, it is possible to achieve both securing of peelability when voltage is applied and securing adhesiveness when voltage is not applied.

(Other ingredients)
You may make it bridge | crosslink by making a crosslinking agent act on an acrylic polymer. Examples of the crosslinking agent include isocyanate crosslinking agents such as toluene diisocyanate and methylene bisphenyl isocyanate. The use ratio of the crosslinking agent is preferably 1 weight or more with respect to 100 parts by weight of the acrylic polymer. When the pressure-sensitive adhesive composition is formed as a layer on the support by crosslinking, the creep resistance and shear resistance of the layer can be improved. A more preferable usage rate is 5 to 10 parts by weight.
The pressure-sensitive adhesive composition includes conductive fillers (carbon particles such as graphite and carbon black; carbon fibers; metal particles such as silver and copper), antistatic agents, colorants, antioxidants, fillers, and the like. It may be.

(Method for producing pressure-sensitive adhesive composition)
The pressure-sensitive adhesive composition can be obtained by stirring an acrylic polymer, an ionic liquid, polyethylene glycol and optionally a crosslinking agent by a known method.

(Use of adhesive composition)
As an application of the pressure-sensitive adhesive composition, an adhesive application between a metal material (for example, aluminum or noble metal) that needs to be recycled and another member can be mentioned. In this application, the metal material can be easily recovered by applying a voltage, which is useful for home appliance recycling, for example.
Moreover, the adhesive use of a sensor and a to-be-adhered body is mentioned. This application is economical because the sensor can be easily recovered by applying a voltage, and the sensor can be used repeatedly.

Furthermore, the use of the collar used for the animal tracking marker is mentioned. In this application, when the tracking is not necessary, the collar can be removed from the animal by applying a voltage to the portion where the collar is joined by remote control.
During the manufacturing process, the pressure-sensitive adhesive composition can be used for temporarily fixing parts. For example, it can be used for temporarily fixing a wafer when dicing an LSI chip. In this application, the temporarily fixed state can be easily released by applying a voltage.
It can be used to bond both satellites when separating them from their enclosures. Conventionally, a method such as jet injection, which is difficult to perform delicate control, has been used for separation. However, if the pressure-sensitive adhesive composition is used, fine control can be performed by applying a voltage, and physical damage to the artificial satellite can be reduced.

(Electrically peelable adhesive products)
An electrically peelable adhesive product (hereinafter also simply referred to as an adhesive product) has a conductive support and an electrically peelable adhesive layer formed thereon. The electrically peelable pressure-sensitive adhesive layer contains the pressure-sensitive adhesive composition.
The shape of the pressure-sensitive adhesive product is not particularly limited, and is determined according to the shape of the conductive support. For example, when the conductive support is a foil, the product is an adhesive tape.

  Examples of the conductive support include metals such as aluminum, copper, silver, and gold, alloys of these metals, foils (thickness less than 100 μm) and plates (thickness of 100 μm or more) made of conductive metal oxide (ITO, etc.) ) And the like, a cloth containing fibers mixed or coated with these metals or alloys, a resin sheet containing these metals or alloys, and a resin plate provided with a layer made of these metals, alloys or conductive metal oxides. Can be mentioned.

(Peeling method)
The adhesive product can be adhered to an adherend. The adherend is not particularly limited, but preferably has conductivity.
Peeling of the adhesive product from the adherend can be performed by applying a voltage to the electrically peelable pressure-sensitive adhesive layer constituting the adhesive product. For example, the terminal is connected to the conductive support and the adherend, and a voltage is applied between the terminals, or the terminal is brought into contact with the conductive support and the electro-releasable adhesive layer, and the voltage is applied between the terminals. Methods and the like.

  The applied voltage is not particularly limited as long as it can be peeled off, but is preferably 1 V or more. The upper limit of the voltage is not particularly defined from the viewpoint of peeling, but is preferably 200 V in consideration of the influence on the voltage application device and the adherend. For example, the application time is preferably 1 second or longer. The upper limit of the application time is not particularly defined from the viewpoint of peeling, but it is preferably 10 minutes considering the influence on the adherend. Furthermore, the temperature at the time of peeling may be room temperature (about 25 ° C.), or may be lower or higher than room temperature. It is preferable to carry out at normal temperature from the ease of peeling work.

EXAMPLES Hereinafter, although this invention is further demonstrated using an Example, this invention is not limited to a following example.
Example 1
(Preparation of acrylic polymer)
A monomer mixture composed of 91 parts by weight of n-butyl acrylate (manufactured by Mitsubishi Chemical), 8 parts by weight of acrylic acid (manufactured by Mitsubishi Chemical), and 1 part by weight of 2-hydroxyethyl methacrylate (manufactured by Nippon Shokubai Co., Ltd.), and a polymerization initiator Azobisisobutyronitrile (AIBN, manufactured by Junsei Chemical Co., Ltd.) 0.2 parts by weight and a solvent (ethyl acetate: toluene (weight ratio) = 9: 1) 186 parts by weight in a nitrogen stream at 85 ° C. Was subjected to a polymerization reaction for 5 hours to obtain an acrylic pressure-sensitive adhesive. The obtained acrylic pressure-sensitive adhesive contained 35% by weight of a resin component (acrylic polymer: weight average molecular weight of about 800,000), and had a viscosity of 7000 mPa · s.

(Preparation of adhesive composition)
100 parts by weight of the acrylic pressure-sensitive adhesive (35 parts by weight of acrylic polymer), 2.0 parts by weight of Coronate L-55E (manufactured by Nippon Polyurethane Co., Ltd.) as an isocyanate-based crosslinking agent, and ionic liquid A (1-hexylpyridinium) Bis (trifluoromethanesulfonyl) imide (manufactured by Kanto Chemical Co., Inc.); 3.5 parts by weight of ionic conductivity 1.8 × 10 ⁻³ S / cm) and polyethylene glycol (PEG, average molecular weight of 400, no. 3.5 parts by weight (manufactured by Ichi Kogyo Seiyaku Co., Ltd.) was added, stirred at room temperature for 10 minutes, and defoamed to obtain an adhesive composition.

(Measurement of ionic conductivity)
The ionic conductivity of the ionic liquid was measured as follows. The measurement was performed by the AC impedance method using a Solartron 1260 frequency response analyzer. Specifically, an ionic liquid is sandwiched between stainless steel using a bipolar cell (manufactured by Toyo System Co., Ltd.), and a certain area A (0.07 cm ² ) and thickness L are measured by a Teflon (registered trademark) spacer. A sample was obtained by controlling to a disk shape of (0.09 cm). By applying a voltage of 10 mV to this sample and changing the frequency defining the amplitude from 1 MHz to 0.1 Hz, curve fitting of the Cole-Cole plot obtained using an equivalent circuit allows bulk resistance ( Ω). The ionic conductivity σ of the ionic liquid was calculated by substituting the sample area A, the sample thickness L, and the bulk resistance Rb into the following equation.
(Formula) σ = L / (Rb × A)
(Σ: ionic conductivity, Rb: bulk resistance, L: sample thickness (cm), A: sample area (cm ² ))
(Preparation of electro-peelable adhesive products)
The pressure-sensitive adhesive composition was applied onto a PET sheet coated with a silicone release agent, and the resulting coating film was dried at 100 ° C. for 2 minutes to obtain an electro-releasable pressure-sensitive adhesive layer having a thickness of 40 μm. Thereafter, an electro-releasable pressure-sensitive adhesive layer was bonded to an aluminum substrate (100 μm) as a conductive support. Then, the electrically peelable adhesive product as an adhesive tape was obtained by making it age at 40 degreeC for 3 days. The obtained electrically peelable adhesive product was subjected to the following evaluation. The results are shown in Table 1.

(Evaluation of electrical peelable adhesive products)
(1) Measurement of adhesive strength The obtained adhesive tape was cut into a width of 25 mm and a length of 250 mm to obtain a sample piece. Place the sample piece on a polished stainless steel plate (adhered body), and reciprocate once in the length direction of the sample piece at a speed of 300 mm / min using a 2 kg rubber roller to obtain an evaluation sample by pressing the sample piece. It was. 30 minutes after pressure bonding, in accordance with JIS Z-0237, the force required for peeling (180 ° peel) at an angle of 180 ° at a tensile speed of 300 mm / min using an autograph AGS-H manufactured by Shimadzu Corporation (Adhesive strength: N / 25 mm) was measured.

After 30 minutes of pressure bonding of the sample sample prepared in the same manner as above, as shown in FIGS. 1A and 1B, electrodes are attached to the conductive support and adherend of the evaluation sample, and a voltage of 100 V is applied for 3 minutes. did. After application, the force required to peel 180 ° was measured in the same manner as described above.
1A and 1B are schematic explanatory views of a voltage application method, in which FIG. 1A is a plan view and FIG. 1B is a cross-sectional view. In the figure, 1 is a conductive support, 2 is an electro-releasable pressure-sensitive adhesive layer, 3 is an adherend, and 4 is a DC power source.

(2) Evaluation of peeling mode When the peelable adhesive layer is observed and the pressure-sensitive adhesive layer is present on both the adherend and the conductive support, it is called “cohesive failure” and is present on the adherend side. The case where it was present only on the conductive support side was defined as “interfacial peeling”.

(3) Evaluation of electrical peelability The electrical peelability was evaluated by the degree of decrease in adhesive strength after voltage application. The ratio (%) of the adhesive strength after voltage application to the adhesive strength before voltage application is calculated as the adhesive strength maintenance rate. When the retention rate is 10% or less, ◎ is assumed that peeling is easy due to the application of voltage, and when it is larger than 10% and 50% or less is marked as ◯, peeling is difficult when it is larger than 50%. X.

Examples 2-8 and Comparative Examples 1-8
Exfoliation was carried out in the same manner as in Example 1 except that the type and amount of ionic liquid used, the type and amount of migration accelerator used, and the thickness of the electro-releasable adhesive layer were changed as shown in Table 1. The adhesive product was obtained (in Table 1, the amount used is converted to the amount based on 100 parts by weight of the acrylic polymer). The obtained electrically peelable adhesive product was evaluated in the same manner as in Example 1. The results are shown in Table 1.

In Table 1, ionic liquid B is N-butyl-N-methylpyrrolidinium bis (trifluoromethanesulfonyl) imide (manufactured by Kanto Chemical Co., Inc.) (ionic conductivity 2.2 × 10 ⁻³ S / cm). Ionic liquid C is 1-ethyl-3-methylimidazolium tetrafluoroborate (manufactured by Kanto Chemical Co., Inc.) (ionic conductivity 1.4 × 10 ⁻² S / cm), and PPG as a migration accelerator is polypropylene Glycol (average molecular weight 4000, manufactured by Sanyo Chemical Industries), dialkyl adipate means a mixture of esters having an alkyl group having 7 to 9 carbon atoms (manufactured by JPLUS).

From Table 1, in Comparative Examples 1 to 6 in which PEG was not added and Comparative Examples 7 and 8 in which a migration accelerator other than PEG was used, the adhesive strength was not sufficiently lowered by voltage application. On the other hand, in the examples, a decrease in adhesive strength due to voltage application was noticeable.
From Examples 1-6, even if the usage-amount of the ionic liquid and the usage-amount of PEG were changed, the adhesive force fall by voltage application was seen.
From Examples 7 and 8, even when the type of the ionic liquid was changed, a decrease in the adhesive strength due to voltage application was observed.

Example 9
Four evaluation samples were collected from the electro-releasable adhesive products of Comparative Example 1, Example 4 and 5, and a voltage of 100 V was applied to each evaluation sample for 3 seconds, 10 seconds, 1 minute, and 3 minutes. The force was measured. The measurement method was the same as in Example 1. The obtained results are shown in Table 2.

The results of Table 2 are plotted in FIG.
From Table 2 and FIG. 2, it can be seen that the adhesive strength of the examples of the electro-peelable adhesive products of Examples is significantly reduced in a short time.

Example 10
Four evaluation samples were collected from the electrically peelable adhesive products of Comparative Example 1, Examples 4 and 5, and the adhesive strength after applying 5V, 10V, 50V and 100V voltages for 3 minutes to each evaluation sample was measured. . The measurement method was the same as in Example 1. The obtained results are shown in Table 3.

The results of Table 3 are plotted in FIG.
From Table 3 and FIG. 3, it can be seen that the adhesive peelable products of the examples all have a significantly reduced adhesive strength at a low voltage.

It is a schematic explanatory drawing of the voltage application method. It is a graph which shows the relationship between adhesive force and voltage application time. It is a graph which shows the relationship between adhesive force and an applied voltage.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conductive support body 2 Electrically peelable adhesive layer 3 Adhering body 4 DC power supply

Claims (7)

An acrylic polymer, an ionic liquid having an ionic conductivity of 10 ⁻⁴ to 10 ⁻² S / cm, and polyethylene glycol, and the ionic liquid and polyethylene glycol are added to 100 parts by weight of the acrylic polymer. On the other hand, it contains in the ratio of 1-40 weight part, respectively, The electrodetachable adhesive composition characterized by the above-mentioned.   The electropeelable pressure-sensitive adhesive composition according to claim 1, wherein the polyethylene glycol has an average molecular weight of 200 to 6000.   The said acrylic polymer consists of a copolymer of the alkyl (meth) acrylate which has a C1-C8 alkyl group, a carboxyl group-containing acrylic monomer, and a hydroxyl group-containing acrylic monomer. The electrically peelable pressure-sensitive adhesive composition according to the description. The ionic liquid is represented by the following formula:

(In the formula, R ¹ is a divalent hydrocarbon group having 2 to 8 carbon atoms which may contain a nitrogen atom constituting a ring together with the nitrogen atom, and R ² and R ³ are the same or different, and An atom or an alkyl group having 1 to 6 carbon atoms (provided that R ³ does not exist when a nitrogen atom forms a double bond with an adjacent carbon atom))
A cation represented by
Br ⁻ , AlCl ₄ ⁻ , Al ₂ Cl ₇ ⁻ , NO ₃ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , CH ₃ COO ⁻ , CF ₃ COO ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (CF ₃ SO ₂ ) ₃ C ⁻ , AsF ₆ ⁻ , SbF ₆ ⁻ , F (HF) _n ⁻ , CF ₃ (CF ₂ ) ₃ SO ₃ ⁻ , (CF ₃ CF ₂ SO ₂ ) ₂ N ⁻ and CF ₃ CF ₂ CF ₂ COO ^- salts with anion selected from electrically-peelable pressure-sensitive adhesive composition according to any one of claims 1 to 3. The ionic liquid is a salt of a cation selected from a pyridinium cation, a cycloaliphatic ammonium cation, and an imidazolium cation, and an anion selected from (CF ₃ SO ₂ ) ₂ N ⁻ and BF ₄ ^—. The electropeelable pressure-sensitive adhesive composition according to any one of claims 1 to 4.   It has an electroconductive support body and the electro-peelable adhesive layer formed on it, The said electro-peelable adhesive layer is an electro-peelable adhesive as described in any one of Claims 1-5. An electropeelable pressure-sensitive adhesive product comprising the composition.   By applying the voltage to the electro-releasable pressure-sensitive adhesive layer after pasting the electro-peelable pressure-sensitive adhesive product according to claim 6 on the adherend so that the electro-releasable pressure-sensitive adhesive layer faces. A method for peeling an electro-peelable pressure-sensitive adhesive product, comprising peeling the electro-peelable pressure-sensitive adhesive product from the adherend.

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