Easily disassembling adhesive sheet, laminated structure, disassembly method, and usage method

Abstract

An easily disassembling adhesive sheet (100) comprises an adhesive layer (10) containing a moisture-cured product of a silyl group-containing resin and a terpene phenolic tackifying resin. The silyl group-containing resin has a polyoxyalkylene structure in a main chain, has, in a portion of the main chain or a side chain, both bonds among a urethane bond and a urea bond or one bond among the urethane bond and the urea bond, and has hydrolyzable silyl groups represented by formula (1) at both ends of the main chain. The easily disassembling adhesive sheet can be repeatedly affixed to and separated from an adherend. (In formula (1), X1 and X2 are each independently a hydroxy group or an alkoxy group, R is a C1-C20 alkyl group, and * is a bonding position.)

Description

Easy-to-dismantle adhesive sheet, laminated structure, dismantling method, and method of use

[0001] The present invention relates to an easily dismantled adhesive sheet, a laminated structure, a dismantling method, and a method of use.

[0002] Adhesive sheets are used in a variety of applications. For example, they are used to join various components that make up products in fields such as office automation equipment, home appliances, automobiles, and construction.

[0003] In recent years, with the aim of building a circular economy, there has been a growing demand for the reuse of used products. Used products include composite components in which various parts are joined together, and when reusing used products, for example, separation of the composite components within the used products is required. When the composite components contained in used products are joined to various adherends with adhesive, it becomes difficult to separate the joined adherends from each other, making it difficult to easily dismantle the composite components. For this reason, for example, Patent Documents 1 and 2 propose adhesive tapes containing acrylic adhesive compositions that take into consideration the separability from adherends.

[0004] Patent Document 1 discloses an acrylic adhesive tape having an adhesive layer containing an adhesive composition characterized by comprising an acrylic polymer (A), a (meth)acrylic polymer (B) having a weight-average molecular weight (Mw) of 1,000 or more and less than 30,000, and thermally expandable microspheres (C).

[0005] Patent Document 2 discloses an easily dismantled adhesive tape having an adhesive layer made of an adhesive composition containing an acrylic polymer and an acid catalyst or acid generator. The adhesive composition described in Patent Document 2 contains an acrylic polymer as a monomer component comprising a (meth)acrylate having an alkyl group having 1 to 14 carbon atoms and a hydroxyl group-containing vinyl monomer, wherein the content of the hydroxyl group-containing vinyl monomer is 10% by mass or more of the monomer component constituting the acrylic polymer, and the acrylic polymer is an acrylic random polymer with a mass-average molecular weight of 100,000 or more.

[0006] Japanese Patent Publication No. 2011-231319 Japanese Patent Publication No. 2014-080524

[0007] For example, a composite member having an adhesive layer formed using an acrylic adhesive composition may be disassembled by heating by reducing the adhesive strength of the adhesive layer at high temperatures. However, when disassembling a composite member joined by an adhesive sheet having such an acrylic adhesive layer, cohesive failure of the adhesive layer may occur when the adhesive layer is separated from the adherend, resulting in adhesive residue on the adherend. For this reason, composite members joined by an adhesive layer made of an acrylic adhesive composition may be difficult to disassemble easily. Furthermore, the adhesive layer made of an acrylic adhesive composition separated from the composite member is prone to cohesive failure, making it difficult to reattach to the adherend. On the other hand, while it is possible to suppress the occurrence of adhesive residue on the adherend by improving the crosslinking density of the adhesive layer made of an acrylic adhesive composition, the adhesive strength at room temperature tends to decrease. Moreover, even if the adhesive layer with improved crosslinking density suppresses adhesive residue on the adherend, the low adhesive strength makes it easy to peel off from the adherend, making it difficult to firmly adhere to the adherend. Therefore, there was a need for further improvements to adhesive sheets that could be easily separated from the adherend.

[0008] The object of the present invention is to provide an easily disassembled adhesive sheet that maintains high adhesive strength to an adherend at room temperature, suppresses adhesive residue when separated from the adherend, and reduces adhesive strength at high temperatures, allowing it to be used multiple times even after separation from the adherend; a laminated structure using the easily disassembled adhesive sheet; a method for disassembling the laminated structure; and a method for using the easily disassembled adhesive sheet.

[0009] [1] An easily disassembled adhesive sheet comprising an adhesive layer containing a moisture-cured product of a silyl group-containing resin and a terpene phenol-based tackifying resin, wherein the silyl group-containing resin has a polyoxyalkylene structure in its main chain, and has both urethane bonds and urea bonds in a part of the main chain or in a side chain, or has either one of the urethane bonds and the urea bonds, and has hydrolyzable silyl groups represented by the following formula (1) at both ends of the main chain, and is capable of repeated attachment and detachment from an adherend.

[0010]

[0011] (In the above formula (1), X １ and X ２ Each of these is independently a hydroxyl group or an alkoxy group, R is an alkyl group having 1 to 20 carbon atoms, and * indicates the bond position.

[0012] [2] An easily dismantled adhesive sheet according to [1], wherein the content of the terpene phenol-based tackifying resin is 20 parts by mass or more and 100 parts by mass or less per 100 parts by mass of the silyl group-containing resin.

[0013] [3] An easily dismantled adhesive sheet according to [1] or [2], wherein the adhesive layer further comprises an acrylic tackifying resin, and the content of the acrylic tackifying resin is 1 part by mass or more and 100 parts by mass or less per 100 parts by mass of the silyl group-containing resin.

[0014] [4] An easily dismantled adhesive sheet as described in [3], wherein the weight-average molecular weight Mw of the acrylic tackifying resin is 300 or more and 10,000 or less.

[0015] [5] An easily dismantled adhesive sheet according to any one of items [1] to [4], comprising a release liner provided on at least one surface of the adhesive layer.

[0016] [6] An easily dismantled adhesive sheet according to any one of [1] to [5], comprising a base material and an adhesive layer provided on at least one surface of the base material.

[0017] [7] An easily dismantled adhesive sheet according to any one of items [1] to [6], wherein the adhesive force at 180° peel at 23°C obtained by performing the operations (S1-1) to (S1-3) below is defined as Ps0, and the operations (S2-1) to (S2-4) below are performed five times as one cycle using an easily dismantled adhesive sheet different from the easily dismantled adhesive sheet used to measure Ps0, and after the completion of the five cycles, the adhesive force retention rate (%) of Ps6 at 23°C obtained by performing the operations (S3-1) to (S3-3) below is defined as Ps6, and the easily dismantled adhesive sheet satisfies the following formula (Equation 1). 120% ≥ (Ps6 / Ps0) × 100 ≥ 90% ... (Equation 1) (S1-1): The first test specimen is obtained by attaching the easily disassembled adhesive sheet for the first test specimen to the adherend for the first test specimen in a 23°C environment. (S1-2): The first test specimen is left standing for 30 minutes in a 23°C environment. (S1-3): After the standing in (S1-2), the 180° peel adhesion strength of the first test specimen at 23°C is measured in accordance with the measurement method specified in JIS Z0237:2022. (S2-1): A second test specimen is obtained by attaching a second easily disassembled adhesive sheet, different from the first test specimen adhesive sheet, to a second test specimen substrate, different from the first test specimen substrate, in a 23°C environment. (S2-2): The second test specimen is left standing in a 120°C environment for 30 minutes. (S2-3): After the standing in (S2-2), the 180° peel-off adhesive strength of the second test specimen at 120°C is measured in accordance with the measurement method specified in JIS Z0237:2022. (S2-4): The second test specimen substrate and the second easily disassembled adhesive sheet, peeled off in (S2-3), are left standing until they cool to 23°C.(S3-1): After cooling as described in (S2-4), the substrate for the second test specimen obtained by performing the operations from (S2-1) to (S2-4) five times is used as the substrate for the third test specimen, and the easily removable adhesive sheet for the second test specimen obtained by performing the operations from (S2-1) to (S2-4) five times is attached to the substrate for the third test specimen in a 23°C environment to obtain the third test specimen, (S3-2): The third test specimen is left to stand for 30 minutes in a 23°C environment, (S3-3): After standing as described in (S3-2), the 180° peel adhesion strength of the third test specimen at 23°C is measured in accordance with the measurement method specified in JIS Z0237:2022.

[0018] [8] In the easily dismantled adhesive sheet described in [7], when the 180° peel-off adhesive force at 120°C obtained by performing the operations (S2-1) to (S2-3) in the first cycle is Ps1, the ratio of Ps1 to Ps0 satisfies the following formula (Equation 2): 0.2 ≥ (Ps1 / Ps0) > 0 ... (Equation 2)

[0019] [9] A laminated structure comprising: a first adherend comprising at least one material selected from the group consisting of metal, glass, and resin; a second adherend composed of the same material as the first adherend or composed of different materials, comprising at least one material selected from the group consisting of metal, glass, and resin; and an easily disassembled adhesive sheet according to any one of [1] to [8] provided between the first adherend and the second adherend and attached to the first adherend and the second adherend.

[0020]

[10] A dismantling method for dismantling a laminated structure, comprising: a step of preparing a laminated structure comprising: a first adherend comprising at least one material selected from the group consisting of metal, glass, and resin; a second adherend composed of the same material as the first adherend or composed of different materials and comprising at least one material selected from the group consisting of metal, glass, and resin; and an easily dismantled adhesive sheet according to any one of [1] to [5], [7], and [8] provided between the first adherend and the second adherend and attached to the first adherend and the second adherend; a step of heating the laminated structure; and a step of separating the first adherend and the second adherend and the easily dismantled adhesive sheet after heating the laminated structure until it cools to the ambient temperature of the dismantling work environment, wherein the easily dismantled adhesive sheet consists only of the adhesive layer.

[0021]

[11] A method for dismantling a laminated structure, comprising: a step of preparing a laminated structure comprising: a first adherend comprising at least one material selected from the group consisting of metal, glass, and resin; a second adherend composed of the same material as the first adherend or composed of different materials and comprising at least one material selected from the group consisting of metal, glass, and resin; and an easily dismantled adhesive sheet according to any one of [1] to [5], [7], and [8] provided between the first adherend and the second adherend and attached to the first adherend and the second adherend; a step of heating the laminated structure; and a step of, after heating the laminated structure and before it cools to the ambient temperature of the dismantling work environment, either the first adherend or the second adherend is not separated from the easily dismantled adhesive sheet, and the other of the first adherend or the second adherend that was not separated from the easily dismantled adhesive sheet is separated from the easily dismantled adhesive sheet, A method for dismantling the easily dismantled adhesive sheet, wherein the easily dismantled adhesive sheet consists only of the adhesive layer.

[0022]

[12] A dismantling method for dismantling a laminated structure, comprising: a step of preparing a laminated structure comprising: a first adherend comprising at least one material selected from the group consisting of metal, glass, and resin; a second adherend composed of the same material as the first adherend or composed of different materials and comprising at least one material selected from the group consisting of metal, glass, and resin; and an easily dismantled adhesive sheet according to any one of [1] to [8] provided between the first adherend and the second adherend and attached to the first adherend and the second adherend; a step of heating the laminated structure; and a step of separating the first adherend and the second adherend and the easily dismantled adhesive sheet after heating the laminated structure until it has cooled to the ambient temperature of the dismantling work environment, wherein the easily dismantled adhesive sheet comprises a base material and adhesive layers provided on both sides of the base material.

[0023]

[13] A method for dismantling a laminated structure, comprising: a step of preparing a laminated structure comprising: a first adherend comprising at least one material selected from the group consisting of metal, glass, and resin; a second adherend composed of the same material as the first adherend or composed of different materials and comprising at least one material selected from the group consisting of metal, glass, and resin; and an easily dismantled adhesive sheet according to any one of [1] to [8] provided between the first adherend and the second adherend and attached to the first adherend and the second adherend; a step of heating the laminated structure; and a step of, after heating the laminated structure and before it cools to the ambient temperature of the dismantling work environment, either the first adherend or the second adherend is not separated from the easily dismantled adhesive sheet, and the other of the first adherend or the second adherend that was not separated from the easily dismantled adhesive sheet is separated from the easily dismantled adhesive sheet, A method for dismantling the easily dismantled adhesive sheet, comprising a base material and adhesive layers provided on both sides of the base material.

[0024]

[14] A method for using an easily dismantled adhesive sheet, comprising the steps of: attaching an adherend comprising at least one material selected from the group consisting of metal, glass, and resin to an easily dismantled adhesive sheet according to any one of items [1] to [8]; separating the adherend and the easily dismantled adhesive sheet; and, after the separation step, attaching the easily dismantled adhesive sheet to the adherend, or another adherend different from the adherend.

[0025] According to one aspect of the present invention, an easily disassembled adhesive sheet is provided that maintains high adhesive strength to an adherend at room temperature, suppresses adhesive residue when separated from the adherend, and reduces adhesive strength at high temperatures, allowing for multiple uses even after separation from the adherend. This also provides a laminated structure using the easily disassembled adhesive sheet, a method for disassembling the laminated structure, and a method for using the easily disassembled adhesive sheet.

[0026] This is a schematic cross-sectional view showing an example of an easily dismantled adhesive sheet according to the first embodiment. This is a schematic cross-sectional view showing another example of an easily dismantled adhesive sheet according to the first embodiment. This is a schematic cross-sectional view showing another example of an easily dismantled adhesive sheet according to the first embodiment. This is a schematic cross-sectional view showing an example of a laminated structure according to the second embodiment. This is a schematic cross-sectional view showing another example of a laminated structure according to the second embodiment. This is a schematic explanatory diagram showing an example of a method for dismantling a laminated structure according to the third embodiment. This is a schematic explanatory diagram showing an example of a method for dismantling a laminated structure according to the third embodiment. This is a schematic explanatory diagram showing an example of a method for dismantling a laminated structure according to the third embodiment. This is a schematic explanatory diagram showing an example of a method for dismantling a laminated structure according to the third embodiment. This is a schematic explanatory diagram showing an example of a method for dismantling a laminated structure according to the third embodiment. This is a schematic explanatory diagram showing another example of a method for dismantling a laminated structure according to the third embodiment. This is a schematic explanatory diagram showing another example of a method for dismantling a laminated structure according to the third embodiment. This is a schematic explanatory diagram showing another example of a method for dismantling a laminated structure according to the third embodiment. This is a schematic explanatory diagram showing another example of a method for dismantling a laminated structure according to the third embodiment.

[0027] The following describes an example of a preferred embodiment of the present invention.

[0028] [First Embodiment] <Easily Disassemblable Adhesive Sheet> The first embodiment is an adhesive sheet (easily disassemblable adhesive sheet) having easily disassemblable properties. The easily disassemblable adhesive sheet according to this embodiment includes an adhesive layer containing a moisture-cured product of a silyl group-containing resin and a terpene phenol-based tackifier resin. The silyl group-containing resin has a polyoxyalkylene structure in the main chain and has both urethane bonds and urea bonds in a part of the main chain or a side chain, or has either one of the urethane bond and the urea bond, and has hydrolyzable silyl groups represented by the following formula (1) at both ends of the main chain. The easily disassemblable adhesive sheet according to this embodiment can be repeatedly attached to and separated from an adherend.

[0029]

[0030] (In the above formula (1), X １ and X ２ are each independently a hydroxy group or an alkoxy group, R is an alkyl group having 1 or more and 20 or less carbon atoms, and * is a bonding position.)

[0031] The adhesive layer of the easily disassemblable adhesive sheet according to this embodiment contains a moisture-cured product of a silyl group-containing resin. The moisture-cured product of the silyl group-containing resin is previously moisture-cured. The easily disassemblable adhesive sheet according to this embodiment is used with the adhesive layer attached to an adherend. "Previously moisture-cured" means that the silyl group-containing resin contained in the adhesive layer formed by the adhesive composition containing the silyl group-containing resin is already in a state of being moisture-cured in the easily disassemblable adhesive sheet according to this embodiment. For this reason, the adhesive layer in the easily disassemblable adhesive sheet according to this embodiment is different from the adhesive layer formed by coating the adherend with the adhesive composition before moisture-curing. For example, the adhesive layer containing the moisture-cured silyl group-containing resin and the adhesive layer formed by coating the adherend with the adhesive composition before moisture-curing have different storage elastic moduli when the adhesive layers before and after moisture-curing are measured under the same conditions. The storage elastic modulus of the adhesive layer containing the moisture-cured silyl group-containing resin is, for example, 70000 Pa or more at room temperature (for example, 23 °C).

[0032] The easily disassembled adhesive sheet according to this embodiment, having the above configuration, maintains high adhesive strength to the adherend at room temperature while suppressing adhesive residue when separated from the adherend. Specifically, the easily disassembled adhesive sheet according to this embodiment achieves high adhesive strength to the adherend at room temperature (for example, 23°C). Here, room temperature refers to the temperature when the laminated structure is not heated by a heating means, and a temperature range of approximately 15°C to 30°C is an example. Furthermore, when the easily disassembled adhesive sheet according to this embodiment is separated from the adherend by heating at a high temperature (for example, 80°C or higher) after being attached to the adherend, adhesive residue on the adherend is suppressed. One example of heating at a high temperature is heating from the adherend side. Therefore, when adherends are joined using the easily dismantled adhesive sheet according to this embodiment, a high adhesive strength is maintained between the adherend and the easily dismantled adhesive sheet at room temperature. When separating the adherend and the easily dismantled adhesive sheet between the time the adherend is heated and the temperature drops to the ambient temperature of the dismantling work environment, the generation of adhesive residue on the adherend is suppressed. As a result, by using the easily dismantled adhesive sheet according to this embodiment, the dismantling of a laminated structure comprising adherends joined with the easily dismantled adhesive sheet according to this embodiment becomes easier, and the adherends can be recovered without leaving any adhesive layer residue. Consequently, the reuse of composite members using the easily dismantled adhesive sheet according to this embodiment becomes easier.

[0033] In addition, the easily disassembled adhesive sheet according to the present embodiment has the above configuration, so that even when it is separated from the adherend by reducing the adhesive force at a high temperature (for example, 80°C or higher), when it returns to room temperature (for example, 23°C), a high adhesive force to the adherend is manifested again. Therefore, the adherend can be repeatedly attached and separated. For this reason, the easily disassembled adhesive sheet according to the present embodiment can be used multiple times. The adherend to which the easily disassembled adhesive sheet according to the present embodiment is attached may be the same as or different from the adherend that was attached and separated when the easily disassembled adhesive sheet according to the present embodiment was first used, and the adherend that is attached and separated again after the second use and subsequent uses of the easily disassembled adhesive sheet according to the present embodiment.

[0034] Even after the easily disassembled adhesive sheet according to the present embodiment is heated to separate it from the adherend, the cohesive failure of the adhesive layer provided in the easily disassembled adhesive sheet is suppressed. For this reason, the easily disassembled adhesive sheet according to the present embodiment has a reduced adhesive force at high temperature compared to the adhesive force at room temperature, and by maintaining a high cohesive force at high temperature, residue is suppressed while separation from the adherend becomes easier. And when the easily disassembled adhesive sheet according to the present embodiment is cooled to room temperature after being heated to a high temperature, the room temperature adhesive force at that time can obtain an adhesive force that is almost equivalent to the room temperature adhesive force before heating again. For this reason, the easily disassembled adhesive sheet according to the present embodiment maintains a high adhesive force at room temperature even after use.

[0035] Therefore, the easily disassembled adhesive sheet according to the present embodiment can be attached to the adherend at room temperature, separated from the adherend at high temperature, and then attached to the adherend again at room temperature, so that the attachment and separation from the adherend can be repeated. That is, the easily disassembled adhesive sheet according to the present embodiment is a reattachable and releasable type of easily disassembled adhesive sheet. Reattachment means that attachment to the same or different adherends as the adherend used for the first time can be performed multiple times, and re - peeling means that separation from the same or different adherends as the adherend used for the first time can be performed multiple times. The easily disassembled adhesive sheet according to the present embodiment has a certain degree of adhesive force even at high temperature, although it is lower than at room temperature. Therefore, after being separated from the adherend at high temperature, it can also be attached to the adherend at high temperature.

[0036] Furthermore, as described above, the easily dismantled adhesive sheet according to this embodiment has high adhesive strength at room temperature, and lower adhesive strength at high temperatures (e.g., 80°C or higher) than at room temperature. In addition, the easily dismantled adhesive sheet according to this embodiment has lower adhesive strength at temperatures higher than room temperature (e.g., 60°C or higher) than at room temperature. Therefore, the easily dismantled adhesive sheet according to this embodiment makes it possible to select the environment in which the easily dismantled adhesive sheet is used based on the desired adhesive strength, such as strong adhesive strength or weak adhesive strength.

[0037] In one embodiment, the easily dismantled adhesive sheet according to this embodiment may include a release liner provided on at least one surface of the adhesive layer.

[0038] In one embodiment, the easily dismantled adhesive sheet according to this embodiment may comprise a base material and the adhesive layer provided on at least one surface of the base material.

[0039] The easily dismantled adhesive sheet according to this embodiment will be described below with reference to the drawings. In the drawings, some parts are enlarged or reduced in size for the sake of clarity.

[0040] [First Embodiment] The first embodiment of the easily dismantled adhesive sheet according to this embodiment is an easily dismantled adhesive sheet consisting only of the adhesive layer described above. Figure 1 shows a schematic cross-sectional view representing an example of an easily dismantled adhesive sheet. As shown in Figure 1, the easily dismantled adhesive sheet 100 consists only of an adhesive layer 10. The adhesive layer 10 contains a moisture-cured product of a silyl group-containing resin as component (A) and a terpene phenol-based tackifying resin as component (B). The moisture-cured product of the silyl group-containing resin is a silyl group-containing resin that has been pre-cured in moisture. The silyl group-containing resin can be cured by reacting with moisture in the atmosphere, and can be cured in moisture with moisture in the atmosphere in an environment at room temperature or a temperature higher than room temperature, for example. The adhesive layer 10 has a first main surface 10A and a second main surface 10B on the opposite side of the first main surface 10A. The main surface is the largest surface of the easily dismantled adhesive sheet 100 and represents the surface facing in the thickness direction. The thickness of the adhesive layer 10 corresponds to the distance between the first main surface 10A and the second main surface 10B of the adhesive layer 10. For convenience, the terms first main surface 10A and second main surface 10B are used to clarify the positional relationship between one surface and the other surface of the easily dismantled adhesive sheet 100. However, in some cases, the first main surface 10A and the second main surface 10B can be used interchangeably, and the first main surface 10A and the second main surface 10B can be used without distinction from each other. The same applies when referring to the main surface in the following explanation.

[0041] (Silyl group-containing resin) The silyl group-containing resin has the following elements (a), (b), and (c): Element (a): The main chain has a polyoxyalkylene structure. Element (b): The main chain or side chain has both urethane bonds and urea bonds, or has either one of the urethane bonds or urea bonds. Element (c): The main chain has hydrolyzable silyl groups represented by formula (1) at both ends.

[0042] The above element (b) corresponds to any of the following elements (b-1), (b-2), (b-3), or (b-4). Element (b-1): The main chain has both urethane bonds and urea bonds in a portion of it. Element (b-2): The main chain has either one of the urethane bonds or the urea bonds in a portion of it. Element (b-3): The side chain has both urethane bonds and urea bonds. Element (b-4): The side chain has either one of the urethane bonds or the urea bonds in it.

[0043] The silyl group-containing resin having elements (a), (b), and (c) above is the silyl group-containing resin before moisture curing. When the silyl group-containing resin is moisture-cured, the hydrolyzable silyl groups represented by formula (1) undergo hydrolysis and dehydration condensation. As a result, the moisture-cured product of the silyl group-containing resin contains virtually no hydrolyzable silyl groups represented by formula (1). In this specification, unless otherwise specified, when the term "silyl group-containing resin" is used, it refers to the silyl group-containing resin before moisture curing, and when the term "moisture-cured product of the silyl group-containing resin" or a similar term is used, it refers to the silyl group-containing resin after moisture curing.

[0044] In formula (1) above, R is an alkyl group having 1 to 20 carbon atoms. From the viewpoint of reactivity in hydrolysis dehydration condensation, R in formula (1) is preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, even more preferably an alkyl group having 1 to 3 carbon atoms, and still more preferably an alkyl group having 1 to 2 carbon atoms. R is also preferably a methyl group.

[0045] In the above formula (1), X １ and X ２ Each of these is independently a hydroxyl group or an alkoxy group. １ and X ２When at least one of them is an alkoxy group, the alkoxy group is preferably an alkoxy group having 1 or more and 12 or less carbon atoms, more preferably an alkoxy group having 1 or more and 6 or less carbon atoms, still more preferably an alkoxy group having 1 or more and 3 or less carbon atoms, and even more preferably an alkoxy group having 1 or more and 2 or less carbon atoms, from the viewpoint of the reactivity of hydrolysis and dehydration condensation. X １ and X ２ are both preferably alkoxy groups. X １ and X ２ are both preferably methoxy groups.

[0046] The silyl group-containing resin can be synthesized, for example, by using a urethane prepolymer having an isocyanate group obtained by reacting a polyol and a polyvalent isocyanate compound, and a silylating agent having a hydrolyzable silyl group represented by the above formula (1) and having an active hydrogen group capable of reacting with an isocyanate group as raw materials, mixing the urethane prepolymer and the silylating agent, and reacting them under predetermined conditions (for example, at 80 ° C for 1 hour) in a nitrogen atmosphere, for example. The reaction is preferably carried out until the disappearance of the absorption peak (2265 cm －１ ) of the isocyanate group measured by infrared spectroscopy (IR) is confirmed. The silyl group-containing resin can be cured by a crosslinking reaction via hydrolysis of the hydrolyzable silyl group represented by the above formula (1) to form a three-dimensional network structure.

[0047] The synthesis of the silyl group-containing resin is not limited to the reaction between the urethane prepolymer and the silylating agent. The silyl group-containing resin can also be synthesized, for example, by reacting a silylating agent having an isocyanate group with a polymer having an active hydrogen group.

[0048] The active hydrogen in both the urethane bond and the urea bond, or the active hydrogen in either the urethane bond or the urea bond, introduced into a part of the main chain or the side chain in the silyl group-containing resin may be substituted with an organic group. Therefore, the allophanate bond is also included in the category of the urethane bond, and the biuret bond is also included in the category of the urea bond.

[0049] In formula (1) above, * may be a bonding position with an alkylene group having 1 to 20 carbon atoms. In formula (1) above, * is preferably a bonding position with an alkylene group having 2 to 16 carbon atoms, and more preferably a bonding position with an alkylene group having 3 to 12 carbon atoms. The alkylene group having 1 to 20 carbon atoms is preferably a linear alkylene group.

[0050] From the viewpoint of strengthening the bonding to the adherend, the specific structure of the terminal portion in the silyl group-containing resin is preferably a structure selected from the group consisting of the following formulas (11), (12), (13), (14), (15), (16), and (17). The structures represented by the following formulas (11) to (17) contain a hydrolyzable silyl group represented by formula (1).

[0051]

[0052]

[0053]

[0054]

[0055]

[0056]

[0057]

[0058] (In equations (11), (12), (13), and (14) above, X １ and X ２ Each is independently a hydroxyl group or an alkoxy group, and R is an alkyl group having 1 to 20 carbon atoms. Ａ and R Ｂ Each is independently an alkyl group having 1 to 20 carbon atoms, * is the bond position, and in formulas (15) and (16), X １ and X ２Each is independently a hydroxyl group or an alkoxy group, R is an alkyl group having 1 to 20 carbon atoms, * is a bond position, and in formula (17), X １ and X ２ Each is independently a hydroxyl group or an alkoxy group, R is an alkyl group having 1 to 20 carbon atoms, L is an alkylene group having 1 to 20 carbon atoms, R Ｃ (where * is an organic group with 1 to 20 carbon atoms, and * indicates the bond position.)

[0059] In the above formula (17), R Ｃ The organic group indicated is preferably an alkyl group having 1 to 20 carbon atoms, an alkylamino group having 1 to 20 carbon atoms, an arylamino group having 6 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms, a heterocyclic group having 2 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, or a cycloalkyl group having 3 to 20 carbon atoms.

[0060] From the viewpoint of exhibiting high adhesive strength and high elastic modulus to the adherend at room temperature, it is preferable that the silyl group-containing resin does not have hydrolyzable silyl groups represented by formula (1) in the side chains, but has hydrolyzable silyl groups represented by formula (1) only at both ends of the main chain. If the silyl group-containing resin does not have hydrolyzable silyl groups represented by formula (1) in the side chains, but has hydrolyzable silyl groups represented by formula (1) only at both ends of the main chain, the crosslinking density between the silyl group-containing resins can be adjusted to an appropriate range, and the compatibility between the silyl group-containing resin and the tackifying resin can be more easily adjusted to a more suitable range.

[0061] The silyl group-containing resin has a polyoxyalkylene structure in its main chain. If the silyl group-containing resin has a polyoxyalkylene structure in its main chain, the adhesive layer 10 can have appropriate flexibility, and the adhesive strength to the adherend can be further improved. The polyoxyalkylene structure is not particularly limited and examples include polyoxypropylene, polyoxyethylene, and combinations thereof. The polyoxyalkylene structure may be present not only in the main chain of the silyl group-containing resin, but also in both the main chain and side chains.

[0062] The weight-average molecular weight Mw of the silyl group-containing resin is preferably 10,000 (10,000) or more, and preferably 200,000 (200,000) or less, from the viewpoint of ease of forming the adhesive layer 10 and having high adhesive strength to the adherend at room temperature. The weight-average molecular weight Mw of the silyl group-containing resin may be 12,000 (12,000) or more, and may be 15,000 (15,000) or more. The weight-average molecular weight Mw of the silyl group-containing resin may be 150,000 (150,000) or less, and may be 100,000 (100,000) or less. The weight-average molecular weight Mw of the silyl group-containing resin can be measured under predetermined conditions using a known molecular weight measuring device such as gel permeation chromatography (GPC).

[0063] The easily disassembled adhesive sheet according to this embodiment is thought to suppress adhesive residue on the adherend when the easily disassembled adhesive sheet according to this embodiment is separated from the adherend, due to the high cohesive force of the silyl group-containing resin contained in the adhesive layer 10. Furthermore, the easily disassembled adhesive sheet according to this embodiment is thought to suppress cohesive breakdown of the adhesive layer due to the high cohesive force of the silyl group-containing resin contained in the adhesive layer 10, and although the adhesive strength decreases at high temperatures, it is thought to have a certain degree of adhesive strength, albeit low. In order to maintain high adhesive strength to the adherend at room temperature, suppress adhesive residue when separated from the adherend, and allow for multiple uses even when separated from the adherend by reducing the adhesive strength at high temperatures, the content of the silyl group-containing resin in the adhesive layer 10 is preferably 20% by mass or more and 90% by mass or less of the total adhesive layer 10 (100% by mass). The content of the silyl group-containing resin is more preferably 25% by mass or more, and even more preferably 30% by mass or more, based on the total amount (100% by mass) of the adhesive layer 10. The content of the silyl group-containing resin is more preferably 80% by mass or less, and even more preferably 75% by mass or less, based on the total amount (100% by mass) of the adhesive layer 10.

[0064] (Terpene phenol-based tackifying resin) The adhesive layer 10 contains a terpene phenol-based tackifying resin. The terpene phenol-based tackifying resin has excellent compatibility with silyl group-containing resins. The inclusion of the terpene phenol-based tackifying resin in the adhesive layer 10 improves the adhesive strength to the adherend at room temperature. The terpene phenol-based tackifying resin is a copolymer of a terpene resin and phenol, and has a double bond derived from terpene and an aromatic ring double bond derived from phenol. The terpene phenol-based tackifying resin may be a fully hydrogenated terpene phenol-based tackifying resin or a partially hydrogenated terpene phenol-based tackifying resin.

[0065] Fully hydrogenated terpene phenol tackifying resins are tackifying resins obtained by substantially completely hydrogenating a terpene phenol tackifying resin. Fully hydrogenated terpene phenol tackifying resins mean tackifying resins in which both the terpene and phenol moieties are hydrogenated completely or nearly completely. Partially hydrogenated terpene phenol tackifying resins are tackifying resins obtained by partially hydrogenating a terpene phenol tackifying resin. Partially hydrogenated terpene phenol tackifying resins mean tackifying resins in which both the terpene and phenol moieties are not hydrogenated completely or nearly completely, but are partially hydrogenated. The method of hydrogenating the terpene phenol tackifying resin is not particularly limited. The hydrogenation ratio of the terpene phenol tackifying resin may be, for example, 50 mol% or more, 65 mol% or more, 80 mol% or more, or 100 mol% or less, relative to 100 mol% of the unsaturated bonds of the terpene phenol resin, from the viewpoint of improving the adhesive strength to the adherend at room temperature. Terpene phenol resins may be used individually or in combination of two or more types.

[0066] Whether a resin is a fully hydrogenated terpene phenol-based tackifying resin or a partially hydrogenated terpene phenol-based tackifying resin can be determined using the FT-IR spectrum obtained by a Fourier transform infrared spectrophotometer (FT-IR). Specifically, the approximately 2960 cm⁻¹ value originating from the carbon-hydrogen bond stretching vibration of the methyl group is used. －１ When the peak height is set to 100, the value of 1625 cm² originates from the stretching vibration of the aromatic carbon-carbon double bond in the phenolic moiety. －１ Above, 1575cm －１ This can be determined by the height of the following peaks.

[0067] The softening point of the terpene phenol-based tackifying resin is not particularly limited and may be, for example, 110°C or higher and 180°C or lower, from the viewpoint of improving the adhesive strength to the adherend at room temperature. The softening point of the terpene phenol-based tackifying resin can be measured by, for example, filling a support ring with the sample, placing a sphere of a certain weight in the center of the support ring in a bath of water or glycerin, raising the bath temperature at a specified rate, and measuring the temperature at which the sample sags due to the weight of the sphere (ring-sphere method).

[0068] From the viewpoint of improving adhesion to the adherend at room temperature, the content of the terpene phenol-based tackifying resin is preferably 20 parts by mass or more and 100 parts by mass or less per 100 parts by mass of the silyl group-containing resin. More preferably, the content of the terpene phenol-based tackifying resin is 30 parts by mass or more, even more preferably 35 parts by mass or more, and still more preferably 40 parts by mass or more, per 100 parts by mass of the silyl group-containing resin. More preferably, the content of the terpene phenol-based tackifying resin is 80 parts by mass or less, even more preferably 70 parts by mass or less, and still more preferably 60 parts by mass or less, per 100 parts by mass of the silyl group-containing resin.

[0069] (Acrylic tackifying resin) The adhesive layer 10 contains a moisture-cured silyl group-containing resin as component (A) and a terpene phenol-based tackifying resin as component (B), and may further contain an acrylic tackifying resin as component (C). The inclusion of an acrylic tackifying resin in the adhesive layer 10 makes it easier to improve the adhesion to the adherend at room temperature.

[0070] Acrylic tackifying resins are composed of, for example, (meth)acrylic acid ester polymers. Examples of (meth)acrylic acid ester polymers include polymers using alkyl (meth)acrylic acid esters as monomers, where the alkyl group has 1 to 20 carbon atoms. Alkyl (meth)acrylic acid esters may have an alicyclic structure within the molecule. The (meth)acrylic acid ester polymer may be a homopolymer of (meth)acrylic acid esters or a copolymer of (meth)acrylic acid esters. The copolymer of (meth)acrylic acid esters may be a copolymer of (meth)acrylic acid ester monomers and other monomers. Acrylic tackifying resins may contain functional groups such as carboxyl groups to facilitate the dismantling of laminated structures, but they may not contain functional groups such as carboxyl groups.

[0071] In this specification, "(meth)acrylic" means both acrylic and methacrylic. The same applies to other similar terms.

[0072] Examples of alkyl acrylate monomers constituting (meth)acrylate polymers include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, myristyl (meth)acrylate, palmityl (meth)acrylate, and stearyl (meth)acrylate. Alkyl (meth)acrylates may be used individually or in combination of two or more.

[0073] Other monomers that constitute the (meth)acrylic acid ester polymer when the (meth)acrylic acid ester polymer is a copolymer include, for example, carboxyl group-containing vinyl monomers, hydroxyl group-containing vinyl monomers, vinyl ether monomers, nitrogen-containing vinyl monomers, aromatic vinyl monomers, and vinyl ester monomers. These other monomers may be used individually, or two or more monomers of the same type may be used in combination. Alternatively, two or more monomers of different types may be used in combination.

[0074] Examples of carboxyl group-containing vinyl monomers include (meth)acrylic acid, maleic acid, itaconic acid, monomethyl maleic acid, monomethyl citraconic acid, 2-carboxyethyl acrylate, 2-carboxyethyl methacrylate, mono(2-acryloyloxyethyl) succinate, and mono(2-methacryloyloxyethyl) succinate. Examples of hydroxyl group-containing vinyl monomers include hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. Examples of vinyl ether monomers include hydroxybutyl vinyl ether. Examples of nitrogen-containing vinyl monomers include monomethylaminoethyl (meth)acrylate, acrylamide, and acryloylmorpholine. Examples of aromatic vinyl monomers include olefins such as ethylene and propylene, and styrene. Examples of vinyl ester monomers include vinyl acetate.

[0075] (Meth)acrylic acid ester copolymers can be produced by known methods such as solution polymerization, emulsion polymerization, bulk polymerization, or suspension polymerization. (Meth)acrylic acid ester copolymers may also be (meth)acrylic acid ester oligomers, from the viewpoint of improving adhesion to the adherend at room temperature.

[0076] The weight-average molecular weight Mw of the acrylic tackifying resin is preferably 300 or more and 10,000 or less. More preferably, the weight-average molecular weight Mw of the acrylic tackifying resin is 500 or more, even more preferably 800 or more, and even more preferably 1,000 or more. More preferably, the weight-average molecular weight Mw of the acrylic tackifying resin is 8,000 or less, even more preferably 6,000 or less, and even more preferably 4,000 or less. The weight-average molecular weight Mw of the acrylic tackifying resin can be measured under predetermined measurement conditions using a known molecular weight measuring device such as gel permeation chromatography (GPC).

[0077] The softening point of the acrylic tackifying resin is not particularly limited and may be, for example, 120°C or higher and 190°C or lower, from the viewpoint of improving the adhesive strength to the adherend at room temperature. The softening point of the acrylic tackifying resin can be determined, for example, by the same measurement method as that used for the softening point of the terpene phenol-based tackifying resin described above.

[0078] From the viewpoint of improving the adhesion to the adherend at room temperature, the content of the acrylic tackifying resin is preferably 1 part by mass or more and 100 parts by mass or less per 100 parts by mass of the silyl group-containing resin. More preferably, the content of the acrylic tackifying resin is 5 parts by mass or more, even more preferably 10 parts by mass or more, and still more preferably 20 parts by mass or more, per 100 parts by mass of the silyl group-containing resin. More preferably, the content of the acrylic tackifying resin is 80 parts by mass or less, even more preferably 70 parts by mass or less, and still more preferably 60 parts by mass or less, per 100 parts by mass of the silyl group-containing resin.

[0079] (Fluorine catalyst) The adhesive layer 10 contains, in addition to a moisture-cured silyl group-containing resin as component (A) and a terpene phenol-based tackifying resin as component (B), it may further contain a fluorine catalyst as component (D). The fluorine catalyst may be used as a fluorine catalyst solution obtained by dissolving a silane coupling agent in a silane coupling agent, which will be described later as component (E), or the fluorine catalyst may be used alone.

[0080] If the adhesive layer 10 contains a fluorine catalyst, it may contain a moisture-cured silyl group-containing resin as component (A), a terpene phenol-based tackifying resin as component (B), and a fluorine catalyst solution (fluorine catalyst as component (D) and silane coupling agent as component (E)), without including an acrylic tackifying resin as component (C). If the adhesive layer 10 contains a fluorine catalyst solution, it may contain a moisture-cured silyl group-containing resin as component (A), a terpene phenol-based tackifying resin as component (B), an acrylic tackifying resin as component (C), and a fluorine catalyst solution (fluorine catalyst as component (D) and silane coupling agent as component (E)).

[0081] The fluorine catalyst may be at least one selected from the group consisting of boron trifluoride and boron trifluoride complexes. From the viewpoint of ease of handling, the fluorine catalyst is preferably a boron trifluoride complex. Examples of boron trifluoride complexes include boron trifluoride amine complexes, boron trifluoride alcohol complexes, boron trifluoride ether complexes, boron trifluoride thiol complexes, boron trifluoride sulfide complexes, boron trifluoride carboxylic acid complexes, and boron trifluoride aqueous complexes. From the viewpoint of excellent stability and catalytic activity, the boron trifluoride complex is preferably a boron trifluoride amine complex. The boron trifluoride complex may be used alone or in combination of two or more types. Using a boron trifluoride complex as a fluorine catalyst makes it easier to suppress the hydrolysis of urethane and urea bonds contained in silyl group-containing resins. This reduces adhesive residue when separating from the adherend, while also improving adhesion at room temperature. Furthermore, it also improves high-temperature adhesion while reducing adhesive residue when separating from the adherend.

[0082] The boron trifluoride amine complex is not particularly limited and includes, for example, boron trifluoride monoethylamine complex, boron trifluoride diethylamine complex, boron trifluoride isopropylamine complex, boron trifluoride chlorophenylamine complex, boron trifluoride-trialylamine complex, boron trifluoride benzylamine complex, and boron trifluoride aniline complex.

[0083] The fluorine catalyst content is preferably 0.001 parts by mass or more and 10 parts by mass or less per 100 parts by mass of the silyl group-containing resin.

[0084] (Silane Coupling Agent) The silane coupling agent is not particularly limited. For example, the silane coupling agent may be an amino group-containing alkoxysilane. Examples of silane coupling agents include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltriethoxysilane, and N-phenyl-3-aminopropyltrimethoxysilane. The silane coupling agent may be used alone or in combination of two or more. The inclusion of the silane coupling agent in the adhesive layer 10 makes it easier for the crosslinking agent to exert its effect.

[0085] The content of the silane coupling agent is preferably 0.01 parts by mass or more and 1 part by mass or less per 100 parts by mass of the silyl group-containing resin.

[0086] The adhesive layer 10 may also contain various additives in addition to the above-mentioned components. Examples of various additives include antioxidants, dehydrating agents (vinylsilane compounds and calcium oxide, etc.), fillers, conductive materials, thermally conductive materials, plasticizers, thixotropes (anhydrous silica and amide wax, etc.), diluents (isoparaffin, etc.), flame retardants (aluminum hydroxide, halogen-based, phosphorus-based, and silicone-based), silicone alkoxy oligomers, pigments, titanate coupling agents, aluminum coupling agents, and drying oils.

[0087] The adhesive layer 10 may be formed from, for example, a hot-melt adhesive composition. In this specification, a hot-melt adhesive composition refers to an adhesive composition of the type that melts and becomes spreadable when heated. The adhesive layer 10 may be formed from, for example, a solvent-type adhesive composition.

[0088] The thickness of the adhesive layer 10 is preferably 1 μm or more and 500 μm or less. More preferably the thickness of the adhesive layer 10 is 5 μm or more, even more preferably 10 μm or more, and even more preferably 20 μm or more. More preferably the thickness of the adhesive layer 10 is 300 μm or less, even more preferably 200 μm or less, and even more preferably 100 μm or less.

[0089] [Second Embodiment] A second embodiment of the easily dismantled adhesive sheet according to this embodiment is provided with a release liner on one or both sides of the adhesive layer. In one embodiment of the second embodiment of the easily dismantled adhesive sheet according to this embodiment, a release liner may be provided on both sides of the adhesive layer 10 described above. The embodiment in which a release liner is provided on both sides of the adhesive layer 10 described above will be described below.

[0090] The following explanation will primarily focus on the differences from the aforementioned easily dismantled adhesive sheet 100, and redundant explanations will be omitted or simplified. Components similar to those of the easily dismantled adhesive sheet 100 will be denoted by the same reference numerals, and their explanations will be omitted or simplified.

[0091] Figure 2A shows a schematic cross-sectional view representing another example of an easily dismantled adhesive sheet, which is an example of an easily dismantled adhesive sheet equipped with a release liner. As shown in Figure 2A, the easily dismantled adhesive sheet 110 is equipped with release liners 20 (first release liner 21 and second release liner 22) on the first main surface 10A and second main surface 10B of the adhesive layer 10 shown in Figure 1, and the adhesive layer 10 is sandwiched between the two release liners 20. That is, the easily dismantled adhesive sheet 110 is laminated in the thickness direction in the order of the first release liner 21, the adhesive layer 10, and the second release liner 22. The second main surface 21B of the first release liner 21 and the first main surface 22A of the second release liner 22 are release surfaces, respectively. The first main surface 10A of the adhesive layer 10 faces the second main surface 21B of the first release liner 21, and the adhesive layer 10 and the first release liner 21 are in direct contact. The second main surface 10B of the adhesive layer 10 faces the first main surface 22A of the second release liner 22, and the adhesive layer 10 and the second release liner 22 are in direct contact.

[0092] (Release Liners) The two release liners 20 are components that protect the adhesive layer 10 until the easily disassembled adhesive sheet 110 is used. When the easily disassembled adhesive sheet 110 is used, the two release liners 20 are peeled off from the adhesive layer 10, exposing the first main surface 10A and the second main surface 10B of the adhesive layer 10, and it is used as the easily disassembled adhesive sheet 100. After the two release liners 20 are peeled off, the first main surface 10A and the second main surface 10B of the adhesive layer 10 are each attached to an object not shown. When the adhesive layer 10 contains the aforementioned acrylic tackifying resin, it exhibits easier peeling force from the release liners 20 compared to when the adhesive layer 10 does not contain the aforementioned acrylic tackifying resin, so when using the easily disassembled adhesive sheet 110, it is easier to peel the release liners 20 from the adhesive layer 10.

[0093] The release liner 20 is not particularly limited, and can be any member having release properties. An example of a release liner 20 is a release material comprising a release substrate and a release agent layer formed by applying a release agent to the release substrate. The release substrate refers to the substrate used in the release liner 20. The release substrate is the substrate that supports the release agent layer of the release liner 20.

[0094] Examples of release substrates include paper substrates (high-quality paper, glassine paper, and clay-coated paper, etc.), laminated paper obtained by laminating a thermoplastic resin such as polyethylene onto a paper substrate, and plastic films such as polyester (polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, etc.) and polyolefins (polypropylene and polyethylene, etc.). Examples of release agents include silicone-based, fluorine-based, and long-chain alkyl-based release agents.

[0095] The thickness of the release liner 20 is not particularly limited and may be, for example, 10 μm or more and 400 μm or less. If the release liner 20 includes a release agent layer, the thickness of the release agent layer may be, for example, 0.01 μm or more and 5 μm or less.

[0096] The two release liners 20 (first release liner 21 and second release liner 22) provided on both sides of the adhesive layer 10 may be the same as or different from each other.

[0097] (Method for manufacturing an easily dismantled adhesive sheet) The easily dismantled adhesive sheet 110 can be obtained, for example, by a manufacturing method having the following steps.

[0098] (Step P1A): A step of preparing an adhesive composition comprising a silyl group-containing resin as component (A1) (the silyl group-containing resin before it becomes a moisture-cured product) and a terpene phenol-based tackifying resin as component (B). (Step P2A): A step of applying the adhesive composition prepared in Step P1A to the surface of one of the release liners 20 (first release liner 21 or second release liner 22) to form a coating film of the adhesive composition, thereby forming an adhesive layer 10 on the surface of one of the release liners 20. (Step P3A): A step of laminating the surface of the other release liner 20 (first release liner 21 or second release liner 22) toward the adhesive layer 10.

[0099] Step P1A is a step of preparing at least the silyl group-containing resin and the terpene phenol-based tackifying resin described in the first embodiment above, and mixing the silyl group-containing resin and the terpene phenol-based tackifying resin so that their content in the adhesive layer 10 is predetermined, thereby preparing an adhesive composition. Specific examples of the silyl group-containing resin and the terpene phenol-based tackifying resin are as described above. The adhesive composition may optionally contain at least one component selected from the group consisting of, for example, an acrylic tackifying resin, a fluorine catalyst, a silane coupling agent, and various additives. Specific examples of these components are as described above. As described above, the adhesive composition may be a hot-melt adhesive composition or a solvent-type adhesive composition.

[0100] Step P2A is a step in which an adhesive layer 10 is formed on one release liner 20 by applying the adhesive composition prepared in step P1A to the surface of one release liner 20. Specifically, the adhesive composition is applied to the first main surface 22A of the second release liner 22 to form a coating of the adhesive composition. This forms an adhesive layer 10 on the second release liner 22. At this time, the first main surface 22A of the second release liner 22 and the second main surface 10B of the adhesive layer 10 are in contact. Step P2A is not limited to the process of applying the adhesive composition to the first main surface 22A of the second release liner 22 to form a coating of the adhesive composition, but may also be adopted as a process of applying the adhesive composition to the surface (second main surface 21B) of the first release liner 21 to form a coating of the adhesive composition and form an adhesive layer 10 on the surface of the first release liner 21.

[0101] The method for applying the adhesive composition to the first main surface 22A of the second release liner 22 is not particularly limited, and known application methods such as bar coating, knife coating, air knife coating, roll knife coating, roll coating, blade coating, die coating, gravure coating, lip coating, curtain coating, dip coating, and squeeze coating can be used.

[0102] Step P3A is a step in which the other release liner 20, which is not the release liner 20 used in step P2A, is laminated on the adhesive layer 10 formed in step P2A. Specifically, the second main surface 21B of the first release liner 21 is laminated toward the first main surface 10A of the adhesive layer 10. Step P3A is not limited to the process of laminating the second main surface 21B of the first release liner 21 toward the adhesive layer 10, but may also be adopted to laminate the surface (first main surface 22A) of the second release liner 22 toward the adhesive layer 10. After that, for example, the silyl group-containing resin contained in the adhesive layer 10 is moisture-cured by leaving it (curing) for a predetermined time (for example, 7 days) in an environment where the temperature is in the range of approximately 15°C to 50°C and the relative humidity is in the range of approximately 45% RH to 85% RH.

[0103] [Third Embodiment] A third embodiment of the easily dismantled adhesive sheet according to this embodiment is an easily dismantled adhesive sheet comprising a base material and the above-described adhesive layer on at least one surface of the base material. In one embodiment of the easily dismantled adhesive sheet according to this embodiment, the adhesive layer 10 described in the first embodiment may be provided on both sides of the base material. The embodiment in which the above-described adhesive layer 10 is provided on both sides of the base material will be described below.

[0104] The following explanation will primarily focus on the differences between the easily dismantled adhesive sheet 100 and the easily dismantled adhesive sheet 110 mentioned above, and redundant explanations will be omitted or simplified. Components similar to those of the easily dismantled adhesive sheet 100 and the easily dismantled adhesive sheet 110 will be given the same reference numerals, and their explanations will be omitted or simplified.

[0105] As shown in Figure 2B, the easily dismantled adhesive sheet 120 comprises a base material 30 and two adhesive layers 10. The base material 30 has a first main surface 30A and a second main surface 30B opposite to the first main surface 30A. The first main surface 30A of the base material 30 is the surface on which the first adhesive layer 11 is placed, and the first main surface 30A of the base material 30 faces the second main surface 11B of the first adhesive layer 11. The second main surface 30B of the base material 30 is the surface on which the second adhesive layer 12 is placed, and the second main surface 30B of the base material 30 faces the first main surface 12A of the second adhesive layer 12. The first adhesive layer 11 is provided in contact with the base material 30, and the second adhesive layer 12 is provided in contact with the base material 30. In other words, the easily disassembled adhesive sheet 120 has a first adhesive layer 11, a base material 30, and a second adhesive layer 12 arranged in this order in the lamination direction. The first main surface 11A of the first adhesive layer 11 and the second main surface 12B of the second adhesive layer 12 are exposed and are adhesive surfaces. The two adhesive layers 10 (the first adhesive layer 11 and the second adhesive layer 12) may be the same or different from each other. As shown in Figure 2B, the easily disassembled adhesive sheet 120 has the base material 30 and the two adhesive layers 10 in contact, but is not limited to this, and any additional layer may be provided between the base material 30 and the two adhesive layers 10, or between the base material 30 and one of the adhesive layers 10, as needed.

[0106] Although not shown in Figure 2B, in order to protect the adhesive surfaces of the first adhesive layer 11 and the second adhesive layer 12 until the easily dismantled adhesive sheet 120 is used, release liners 20 as shown in Figure 2A may be attached to both the first main surface 11A of the first adhesive layer 11 and the second main surface 12B of the second adhesive layer 12. In this case, the first release liner 21 is provided in contact with the first adhesive layer 11, and the second release liner 22 is provided in contact with the second adhesive layer 12. Furthermore, the release liner 20 may be either the first release liner 21 or the second release liner 22, or both the first release liner 21 and the second release liner 22 may be used.

[0107] (Base material) The base material 30 is not particularly limited, and examples include plastic films. Examples of resins constituting the plastic film include polyolefins (polyethylene and polypropylene, etc.), polyesters (polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate, etc.), polyimide, polyetherimide, polyether ketone, polyether ether ketone, polycarbonate, polymethyl methacrylate, triacetylcellulose, polynorbornene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, vinyl chloride, polyurethane acrylate, polyethersulfone, and polyphenyl ethersulfone.

[0108] The thickness of the substrate 30 is not particularly limited and may be, for example, 5 μm or more and 500 μm or less. The thickness of the substrate 30 may be, for example, 10 μm or more and 15 μm or more. The thickness of the substrate 30 may be, for example, 200 μm or less and 100 μm or less.

[0109] (Method for manufacturing an easily dismantled adhesive sheet) The easily dismantled adhesive sheet 120 can be obtained, for example, by a manufacturing method having the following steps. It is preferable to manufacture the easily dismantled adhesive sheet 120 using a release liner (for example, the release liner 20 shown in Figure 2A) which is not shown in Figure 2B. Below is an example of a manufacturing method using both the first release liner 21 and the second release liner 22 shown in Figure 2A.

[0110] (Step P1B): A step of preparing an adhesive composition comprising a silyl group-containing resin as component (A1) and a terpene phenol-based tackifying resin as component (B). (Step P2B): A step of applying the adhesive composition prepared in Step P1B to the surface of one of the release liners 20 (first release liner 21 or second release liner 22) to form a coating film of the adhesive composition, thereby forming one adhesive layer 10 (first adhesive layer 11 or second adhesive layer 12) on the surface of one of the release liners 20. (Step P3B): A step of laminating the substrate 30 toward the adhesive layer 10 formed on the surface of one of the release liners 20 (first release liner 21 or second release liner 22). (Step P4B): A step in which the adhesive composition prepared in Step P1B is applied to the surface of the substrate 30 to form a coating film of the adhesive composition, thereby forming the other adhesive layer 10 (first adhesive layer 11 or second adhesive layer 12) on the surface of the substrate 30. (Step P5B): A step in which the other release liner 20 (first release liner 21 or second release liner 22) is laminated toward the other adhesive layer 10 formed on the surface of the substrate 30.

[0111] Step P1B is the same as step P1A described above. Specifically, the step of forming the first adhesive layer 11 or the second adhesive layer 12 includes, as step P1B-1, the step of preparing an adhesive composition for forming the first adhesive layer 11, which includes a silyl group-containing resin as component (A1) and a terpene phenol-based tackifying resin as component (B), and as step P1B-2, the step of preparing an adhesive composition for forming the second adhesive layer 12, which includes a silyl group-containing resin as component (A1) and a terpene phenol-based tackifying resin as component (B). The adhesive composition prepared in step P1B-1 and the adhesive composition prepared in step P1B-2 may be the same or different from each other.

[0112] Step P2B is the same as step P2A described above. Specifically, for example, if the first adhesive layer 11 is to be formed first, the first adhesive composition for forming the first adhesive layer 11 is applied to the surface of the first release liner 21 to form a coating of the adhesive composition for forming the first adhesive layer 11, thereby forming the first adhesive layer 11 on the surface of the first release liner 21.

[0113] Step P3B is the same as step P3A described above, except that instead of laminating the other release liner 20, the base material 30 is laminated.

[0114] Step P4B is the same as step P2B, except that it involves forming an adhesive layer 10 by forming a coating film of the adhesive composition on the substrate 30. If a first adhesive layer 11 is formed in step P2B, then step P4B becomes a step in which a second adhesive layer 12 is formed.

[0115] Process P5B is the same process as process P3A described above.

[0116] Furthermore, the easily dismantled adhesive sheet 120 can also be manufactured using a different method. In this alternative manufacturing method, steps P1B and P2B are the same, while steps P3B to P5B described above differ from steps P3C and P4C described below.

[0117] (Step P3C): A step in which the prepared adhesive composition is applied to the surface of the other release liner 20 (first release liner 21 or second release liner 22) to form a coating film of the adhesive composition, thereby forming the other adhesive layer 10 (first adhesive layer 11 or second adhesive layer 12) on the other release liner 20. (Step P4C): A step in which the first adhesive layer 10 (first adhesive layer 11 or second adhesive layer 12) formed in step P2B is laminated toward one side of the base material 30, and the other adhesive layer 10 (first adhesive layer 11 or second adhesive layer 12) formed in step P3C is laminated toward the other side of the base material 30.

[0118] The easily disassembled adhesive sheet 100 and the easily disassembled adhesive sheet 120 can each be used, for example, to join components used in at least a part of a large product such as a home appliance. The easily disassembled adhesive sheet 100 and the easily disassembled adhesive sheet 120 according to this embodiment can also each be used, for example, to join components used in at least a part of a small product such as an electronic device.

[0119] An example of an easily dismantled adhesive sheet according to this embodiment has been described above with reference to the drawings, but the easily dismantled adhesive sheet according to this embodiment is not limited thereto. The easily dismantled adhesive sheet according to this embodiment can take various forms as long as it has the above configuration. For example, the shape of the easily dismantled adhesive sheet according to this embodiment may be any shape appropriate to the purpose, for example, it may be rectangular, triangular, polygonal, circular, or elliptical. Furthermore, the release liner 20 is not limited to being provided on both sides of the adhesive layer 10, but may be provided on one side of the adhesive layer 10 depending on the purpose. Moreover, the adhesive layer 10 is not limited to being provided on both sides of the base material 30, but may be provided on one side of the base material 30 depending on the purpose.

[0120] <Characteristics of the easily dismantled adhesive sheet> The adhesive strength of the easily dismantled adhesive sheet according to this embodiment preferably has the following characteristics.

[0121] (Adhesion retention rate) As described above, the easily disassembled adhesive sheet according to this embodiment has high adhesive strength at room temperature and lower adhesive strength at high temperatures than at room temperature. Furthermore, even if the easily disassembled adhesive sheet according to this embodiment is separated from the adherend by a decrease in adhesive strength at high temperatures, high adhesive strength to the adherend is re-emerged when it returns to room temperature, so it can be repeatedly attached to and separated from the adherend and used multiple times.Therefore, the adhesive strength of the easily disassembled adhesive sheet according to this embodiment maintains its high adhesive strength at room temperature even when it is used multiple times by repeatedly attaching it at room temperature and separating it at high temperatures.

[0122] In the easily dismantled adhesive sheet according to this embodiment, the 180° peel-off adhesive force at 23°C obtained by performing the operations (S1-1) to (S1-3) below is defined as Ps0. Using an easily dismantled adhesive sheet different from the one used to measure Ps0, the operations (S2-1) to (S2-4) below are performed five times, with one cycle being defined as Ps6. After the five cycles are completed, the 180° peel-off adhesive force at 23°C obtained by performing the operations (S3-1) to (S3-3) below is defined as Ps6. Preferably, the adhesion retention rate (%) of Ps6 relative to Ps0 satisfies the following formula (Equation 1). If the easily dismantled adhesive sheet according to this embodiment satisfies the following formula (Equation 1), it is likely that the easily dismantled adhesive sheet according to this embodiment can be used multiple times by repeatedly applying it at room temperature and separating it at high temperature. Note that the upper limit of the following formula (Equation 1) may exceed 100%. 120% ≥ (Ps6 / Ps0) × 100 ≥ 90% ... (Math 1)

[0123] (S1-1): The first test specimen is obtained by attaching the easily disassembled adhesive sheet for the first test specimen to the substrate at 23°C. (S1-2): The first test specimen is left standing at 23°C for 30 minutes. (S1-3): After the standing in (S1-2), the 180° peel adhesion strength of the first test specimen at 23°C is measured in accordance with the measurement method specified in JIS Z0237:2022.

[0124] (S2-1): A second test specimen is obtained by attaching a second easily disassembled adhesive sheet, different from the first test specimen adhesive sheet, to a second test specimen substrate, different from the first test specimen substrate, in a 23°C environment. (S2-2): The second test specimen is left standing in a 120°C environment for 30 minutes. (S2-3): After the standing in (S2-2), the 180° peel-off adhesive strength of the second test specimen at 120°C is measured in accordance with the measurement method specified in JIS Z0237:2022. (S2-4): The second test specimen substrate and the second easily disassembled adhesive sheet, peeled off in (S2-3), are left standing until they cool to 23°C.

[0125] (S3-1): After cooling as described in (S2-4), the substrate for the second test specimen obtained by performing the operations from (S2-1) to (S2-4) five times is used as the substrate for the third test specimen, and the easily removable adhesive sheet for the second test specimen obtained by performing the operations from (S2-1) to (S2-4) five times is attached to the substrate for the third test specimen in a 23°C environment to obtain the third test specimen, (S3-2): The third test specimen is left to stand for 30 minutes in a 23°C environment, (S3-3): After standing as described in (S3-2), the 180° peel adhesion strength of the third test specimen at 23°C is measured in accordance with the measurement method specified in JIS Z0237:2022.

[0126] The easily disassembled adhesive sheet and adherend used for the first test specimen during operations (S1-1) to (S1-3) are not reused as the easily disassembled adhesive sheet and adherend for the second test specimen during five cycles of operations (S2-1) to (S2-4). Although the easily disassembled adhesive sheets used for the first test specimen and the easily disassembled adhesive sheet for the second test specimen are different, they are both easily disassembled adhesive sheets made of the same material and have the same configuration. The same applies to the adherend for the first test specimen and the adherend for the second test specimen. Therefore, although the first and second test specimens are different, they have the same configuration.

[0127] The easily disassembled adhesive sheet and adherend for the second test specimen used during operations (S2-1) to (S2-4) of the second cycle are the same as the easily disassembled adhesive sheet and adherend for the second test specimen that were cooled to 23°C in (S2-4) of the first cycle. Similarly, the easily disassembled adhesive sheet and adherend for the second test specimen used during operations (S2-1) to (S2-4) of the third to fifth cycles are the same as the easily disassembled adhesive sheet and adherend for the second test specimen that were cooled to 23°C in (S2-4) of the second to fourth cycles. In other words, the easily disassembled adhesive sheet and adherend for the second test specimen used in the first cycle are reused in the next cycle and used until operation (S2-4) of the fifth cycle is performed.

[0128] In the fifth cycle (S2-4), the easily disassembled adhesive sheet and adherend for the second test specimen, cooled to 23°C, are used as the easily disassembled adhesive sheet and adherend for the third test specimen in (S3-1), respectively. Then, operations (S3-1) through (S3-3) are performed. In other words, the easily disassembled adhesive sheet and adherend used when performing operations (S2-1) through (S2-4) for five cycles are reused when performing operations (S3-1) through (S3-3).

[0129] From the viewpoint of enabling the easily disassembled adhesive sheet according to this embodiment to be used multiple times by repeatedly applying it at room temperature and separating it at high temperature, the value of formula (Equation 1) may be 115% or less, 110% or less, or 105% or less. Similarly, the value of formula (Equation 1) is more preferably 92% or more, even more preferably 94% or more, and even more preferably 97% or more.

[0130] (Ratio of adhesive strength at room temperature to adhesive strength at high temperature) As described above, the easily dismantled adhesive sheet according to this embodiment has a lower adhesive strength at high temperature compared to the adhesive strength at room temperature, but it still has adhesive strength at high temperatures.

[0131] In the easily dismantled adhesive sheet according to this embodiment, when the 180° peel-off adhesive force at 120°C obtained by performing the operations (S2-1) to (S2-3) in the first cycle is denoted as Ps1, it is preferable that the ratio of Ps1 to Ps0 satisfies the following formula (Equation 2): 0.20 ≥ (Ps1 / Ps0) > 0 ... (Equation 2)

[0132] The easily disassembled adhesive sheet according to this embodiment, if it satisfies formula (Equation 2), has lower adhesive strength at high temperatures compared to adhesive strength at room temperature, making it easier to separate from the adherend. As a result, adhesive residue is more easily suppressed. Furthermore, the easily disassembled adhesive sheet according to this embodiment has lower adhesive strength at high temperatures compared to adhesive strength at room temperature, and has appropriate adhesive strength at high temperatures, making it suitable for use in high-temperature environments when weak adhesive strength is required. From this viewpoint, the value of formula (Equation 2) is more preferably 0.19 or less, even more preferably 0.18 or less, and even more preferably 0.17 or less. From a similar viewpoint, the value of formula (Equation 2) is more preferably 0.10 or more, even more preferably 0.12 or more, and even more preferably 0.14 or more. The left and right sides of formula (Equation 2) can be arbitrarily selected from the above preferred upper and lower limits. Formula (Equation 2) is also preferably within the range represented by, for example, the following formula (Equation 2A). The left and right sides of the following equation (Equation 2A) can also be arbitrarily selected from the above preferred upper and lower limits: 0.19 ≥ (Ps1 / Ps0) ≥ 0.10 ... (Equation 2A)

[0133] (Adhesion at Room Temperature) When the adhesion of the easily dismantled adhesive sheet according to this embodiment at 23°C is defined as the adhesion at room temperature, the adhesion at room temperature is preferably 5.0 N / 25 mm or more, more preferably 7.0 N / 25 mm or more, even more preferably 10.0 N / 25 mm or more, even more preferably 15.0 N / 25 mm or more, and even more preferably 20.0 N / 25 mm or more. The adhesion at room temperature is also preferably, for example, 30.0 N / 25 mm or less.

[0134] (High-temperature adhesive strength) When the adhesive strength of the easily dismantled adhesive sheet according to this embodiment at 120°C is defined as the high-temperature adhesive strength, it is preferably 1.0 N / 25 mm or more, more preferably 1.2 N / 25 mm or more, even more preferably 1.5 N / 25 mm or more, even more preferably 1.8 N / 25 mm or more, and even more preferably 2.0 N / 25 mm or more. It is also preferable that the high-temperature adhesive strength be, for example, 5.0 N / 25 mm or less.

[0135] (Effects of the First Embodiment) According to this embodiment, the following effects can be achieved. (1A): Since the easily dismantled adhesive sheet 100 and the easily dismantled adhesive sheet 120 each have an adhesive layer 10 comprising a moisture-cured silyl group-containing resin having hydrolyzable silyl groups of a specific structure and a terpene phenol-based tackifying resin, high adhesive strength to the adherend is maintained at room temperature. (2A): Since the easily dismantled adhesive sheet 100 and the easily dismantled adhesive sheet 120 each have an adhesive layer 10 comprising a moisture-cured silyl group-containing resin having hydrolyzable silyl groups of a specific structure and a terpene phenol-based tackifying resin, when a laminated structure made by attaching the easily dismantled adhesive sheet 100 or the easily dismantled adhesive sheet 120 to an adherend is dismantled, adhesive residue on the adherend is suppressed due to the cohesive force of the silyl group-containing resin. (3A): When the adhesive layer 10 of the easily disassembled adhesive sheet 100 and the easily disassembled adhesive sheet 120 further contains an acrylic tackifying resin, the adhesive strength at room temperature is improved. (4A): When the adhesive layer 10 of the easily disassembled adhesive sheet 100 and the easily disassembled adhesive sheet 120 further contains an acrylic tackifying resin, they exhibit a light peeling force, so that the release liner 20 and the adhesive layer 10 can be easily separated with a low peeling force. (5A): Since the easily disassembled adhesive sheet 100 and the easily disassembled adhesive sheet 120 each have an adhesive layer 10 containing a moisture-cured silyl group-containing resin having hydrolyzable silyl groups of a specific structure and a terpene phenol-based tackifying resin, they can be repeatedly attached to and removed from the adherend even when separated from the adherend by reducing the adhesive strength at high temperatures. As a result, the easily disassembled adhesive sheet 100 and the easily disassembled adhesive sheet 120 can each be used multiple times even after being separated from the adherend. (6A): The easily dismantled adhesive sheet 100 and the easily dismantled adhesive sheet 120 each have an adhesive layer 10 comprising a moisture-cured silyl group-containing resin having hydrolyzable silyl groups of a specific structure and a terpene phenol-based tackifying resin. Therefore, they have high adhesive strength at room temperature and lower adhesive strength at high temperatures than at room temperature.As a result, the easily dismantled adhesive sheet 100 and the easily dismantled adhesive sheet 120 can be used in different environments depending on the desired adhesive strength.

[0136] [Second Embodiment] <Laminated Structure> The second embodiment is a laminated structure. The laminated structure according to the second embodiment comprises: a first adherend comprising at least one material selected from the group consisting of metal, glass, and resin; a second adherend composed of the same material as the first adherend or composed of different materials, comprising at least one material selected from the group consisting of metal, glass, and resin; and an easily detachable adhesive sheet according to the first embodiment provided between the first adherend and the second adherend and attached to the first adherend and the second adherend.

[0137] The laminated structure according to this embodiment will be described below with reference to the drawings. In the drawings, some parts are shown enlarged or reduced in size for the sake of clarity.

[0138] The following description will mainly explain the differences from the easily dismantled adhesive sheets 100, 110, and 120 of the first embodiment, and redundant explanations will be omitted or simplified. Components similar to those of the easily dismantled adhesive sheets 100, 110, and 120 of the first embodiment will be denoted by the same reference numerals, and their explanations will be omitted or simplified.

[0139] [First Embodiment] Figure 3A shows a schematic cross-sectional view of a laminated structure 200 as an example of this embodiment. The laminated structure 200 is an example of the first embodiment of the laminated structure according to this embodiment. The laminated structure 200 uses the easily disassembled adhesive sheet 100 described in the first embodiment, and the easily disassembled adhesive sheet 100 consists only of an adhesive layer 10. The laminated structure 200 is also an embodiment in which the easily disassembled adhesive sheet 110 described in the second embodiment is used. In this case, the laminated structure 200 is manufactured, for example, by removing two release liners 20 from the easily disassembled adhesive sheet 110 and attaching the adhesive layer 10 to two adherends 40. The order in which the adhesive layer 10 is attached to the two adherends 40 is not limited. For example, the adhesive layer 10 and the two adherends 40 may be attached at the same time, or one adherend 40 and the other adherend 40 may be attached to the adhesive layer 10 sequentially.

[0140] As shown in Figure 3A, the laminated structure 200 comprises two adherends 40 (a first adherend 41 and a second adherend 42) and an easily disassembled adhesive sheet 100, with the first adherend 41, the easily disassembled adhesive sheet 100, and the second adherend 42 being laminated in this order in the lamination direction. In the laminated structure 200, the second main surface 41B of the first adherend 41 is attached to the first main surface 10A of the adhesive layer 10, and the first main surface 42A of the second adherend 42 is attached to the second main surface 10B of the adhesive layer 10, thereby joining the two adherends 40 via the easily disassembled adhesive sheet 100.

[0141] (Adherends) The two adherends 40 (first adherend 41 and second adherend 42) each contain at least one material selected from the group consisting of metal, glass, and resin. The two adherends 40 may each be a composite material containing these materials. If the adherend 40 is a composite material, the adherend 40 may be, for example, glass with metal deposited on it, resin with metal deposited on it, or glass with a resin bonded to it with metal deposited on it. In addition, the adherend 40 may be glass with resin laminated on it, metal with resin laminated on it, or metal with a glass coating.

[0142] The material of the metal substrate is not particularly limited, and examples include metals such as aluminum. The metal is not limited to pure metals such as aluminum, but may also be an aluminum alloy, stainless steel, or other alloy. The material of the glass substrate is not particularly limited, and examples include soda glass and borosilicate glass. The material of the resin substrate is not particularly limited, and examples include various resins such as polyolefins (polypropylene and polyethylene, etc.), polyesters (polyethylene terephthalate, polybutylene terephthalate, and polybutylene terephthalate, etc.), polycarbonate, polymethyl (meth)acrylate, urethane, and melamine. The resin may also be a foamed resin.

[0143] The two adherends 40 may be made of the same material or different materials. If the two adherends 40 are different, for example, the first adherend 41 may contain glass and the second adherend 42 may contain metal. Alternatively, the first adherend 41 may contain glass and the second adherend 42 may contain resin. The shapes of the two adherends 40 are not particularly limited; for example, they may be plate-shaped or block-shaped. The two adherends 40 may be made of the same shape and dimensions or different shapes and dimensions. The adherends 40 may be formed of materials, shapes, and dimensions appropriate to the purpose.

[0144] The first adherend 41 may have a printed layer (not shown) on at least one of its first main surface 41A and second main surface 41B. For example, the second main surface 41B of the first adherend 41 may have a printed layer, and the easily removable adhesive sheet 100 may be attached to the printed layer. Alternatively, the second main surface 41B of the first adherend 41 may have a metal vapor deposition layer (not shown), and the metal vapor deposition layer may have a printed layer, and the easily removable adhesive sheet 100 may be attached to the printed layer. If a printed layer is provided, it may be formed by a printing method such as offset printing, grab-a-printing, flexographic printing, or screen printing. In addition, at least one of the first main surface 41A and second main surface 41B may be coated (not shown). The second adherend 42, like the first adherend 41, may have a printed layer (not shown), a metal vapor deposition layer (not shown), or a coated (not shown).

[0145] [Second Embodiment] Figure 3B shows a schematic cross-sectional view of a laminated structure 220 as another example of this embodiment. The laminated structure 220 is an example of a second embodiment of the laminated structure according to this embodiment. The laminated structure 220 uses the easily dismantled adhesive sheet 120 described in the third embodiment of the first embodiment, and the laminated structure 220 comprises a base material 30 and adhesive layers 10 provided on both sides of the base material 30.

[0146] The laminated structure 220 has the same configuration as the laminated structure 200, except that the easily disassembled adhesive sheet 100 is replaced with an easily disassembled adhesive sheet 120. A specific example of the easily disassembled adhesive sheet 120 is as described in the third aspect of the first embodiment. As shown in Figure 3B, the laminated structure 220 comprises two adherends 40 (a first adherend 41 and a second adherend 42) and an easily disassembled adhesive sheet 120, and has a structure in which the first adherend 41, the easily disassembled adhesive sheet 120, and the second adherend 42 are laminated in this order. Since the easily dismantled adhesive sheet 120 has adhesive layers 10 on both sides of the base material 30, the second main surface 41B of the first adherend 41 is attached to the first main surface 11A of the first adhesive layer 11 on the easily dismantled adhesive sheet 120, and the first main surface 42A of the second adherend 42 is attached to the second main surface 12B of the second adhesive layer 12 on the easily dismantled adhesive sheet 120. As a result, the two adherends 40 are joined together via the easily dismantled adhesive sheet 120.

[0147] The laminated structure 200 and the laminated structure 220 may each be at least a part of a large product such as a home appliance. The laminated structure 200 and the laminated structure 220 may each be at least a part of a small product such as an electronic device.

[0148] Although an example of a laminated structure according to this embodiment has been described above with reference to the drawings, the laminated structure according to this embodiment is not limited thereto. The laminated structure according to this embodiment can take various forms as long as it has the above configuration. For example, the laminated structure according to this embodiment is not limited to the case in which the easily disassembled adhesive sheet is attached to the entire surface of the first adherend and the second adherend, but may be attached to a part of the first adherend, or to a part of the second adherend, or to a part of the first adherend and a part of the second adherend. Furthermore, the laminated structure according to this embodiment may include a third adherend arranged in parallel with the first adherend, or a fourth adherend arranged in parallel with the second adherend, or a third adherend arranged in parallel with the first adherend and a fourth adherend arranged in parallel with the second adherend, and each of these adherends may be attached with the easily disassembled adhesive sheet according to the first embodiment and joined via the easily disassembled adhesive sheet according to the first embodiment.

[0149] (Effects of the Second Embodiment) According to this embodiment, the following effects can be achieved. (1B): Since the easily dismantled adhesive sheet 100 and the easily dismantled adhesive sheet 120 are equipped with the adhesive layer 10 described in the first embodiment, a high adhesive strength at room temperature is maintained for each of the two adherends 40 (the first adherend 41 and the second adherend 42). For this reason, the laminated structure 200 or laminated structure 220 made by attaching the easily dismantled adhesive sheet 100 or the easily dismantled adhesive sheet 120 to the two adherends 40 is firmly bonded at room temperature. (2B) Since the easily dismantled adhesive sheet 100 and the easily dismantled adhesive sheet 120 are equipped with the adhesive layer 10 described in the first embodiment, the adhesive strength at high temperatures is lower than the adhesive strength at room temperature, but they still have adhesive strength. Therefore, a laminated structure 200 or laminated structure 220 having weak adhesive strength can be constructed in an environment with a temperature higher than room temperature (e.g., 60°C or higher) or a high temperature (e.g., 80°C or higher).

[0150] [Third Embodiment] <Dismantling Method> The third embodiment is a dismantling method for dismantling a laminated structure. One aspect of the dismantling method for a laminated structure according to this embodiment includes the steps of: preparing a laminated structure comprising: a first adherend comprising at least one material selected from the group consisting of metal, glass, and resin; a second adherend composed of the same material as the first adherend or composed of different materials and comprising at least one material selected from the group consisting of metal, glass, and resin; and an easily dismantled adhesive sheet according to the first embodiment provided between the first adherend and the second adherend and attached to the first adherend and the second adherend; heating the laminated structure; and separating the first adherend, the second adherend and the easily dismantled adhesive sheet after heating the laminated structure until it cools to the ambient temperature of the dismantling work environment. The adhesive sheet according to the first embodiment consists only of an adhesive layer (i.e., the first aspect of the first embodiment), or comprises a substrate and the adhesive layer provided on both sides of the substrate (i.e., the third aspect of the first embodiment). The laminated structure is the laminated structure according to the second embodiment.

[0151] One embodiment of a method for dismantling a laminated structure according to this embodiment comprises: a step of preparing a laminated structure comprising: a first adherend comprising at least one material selected from the group consisting of metal, glass, and resin; a second adherend composed of the same material as the first adherend or composed of different materials and comprising at least one material selected from the group consisting of metal, glass, and resin; and an easily dismantled adhesive sheet according to the first embodiment provided between the first adherend and the second adherend and attached to the first adherend and the second adherend; a step of heating the laminated structure; and after heating the laminated structure, while it is cooling down to the ambient temperature of the dismantling work environment, a step of not separating either the first adherend or the second adherend from the easily dismantled adhesive sheet, and separating the other of the first adherend or the second adherend that was not separated from the easily dismantled adhesive sheet from the easily dismantled adhesive sheet. The adhesive sheet according to the first embodiment consists only of an adhesive layer (i.e., the first aspect of the first embodiment), or comprises a substrate and the adhesive layer provided on both sides of the substrate (i.e., the third aspect of the first embodiment). The laminated structure is the laminated structure according to the second embodiment.

[0152] In the step of heating the laminated structure in this embodiment, the method of heating the laminated structure to be heated is not particularly limited. Examples of the steps for heating the laminated structure in this embodiment include the following:

[0153] In the dismantling method according to this embodiment, the step of heating the laminated structure may be a method of heating the laminated structure by leaving it in a high-temperature environment. In the dismantling method according to this embodiment, the step of heating the laminated structure may be a method of heating the laminated structure by bringing a heating medium into contact with at least one of the first adherend and the second adherend. In the dismantling method according to this embodiment, the step of heating the laminated structure may be a method of bringing a heating means for heating the laminated structure into contact with the surface of the first adherend or the second adherend, and heating the laminated structure from the surface side of the first adherend or the second adherend while the heating means is in contact with the first adherend or the second adherend.

[0154] First, we will describe an embodiment of the dismantling method according to this embodiment, which includes a step of bringing a heating means for heating the laminated structure into contact with the surface of the first or second adherend, and heating the laminated structure from the side of the first or second adherend while the heating means is in contact with the first or second adherend (the first to fourth embodiments).

[0155] A first aspect of the dismantling method according to the third embodiment includes the steps of: preparing the laminated structure described in the second embodiment (step S1); bringing a heating means for heating the laminated structure into contact with the surface of the first adherend or the second adherend provided on the laminated structure, and heating the laminated structure from the first adherend or the second adherend side while the heating means is in contact with the first adherend or the second adherend (step S2); and separating the first adherend and the second adherend and the easily dismantled adhesive sheet after heating the laminated structure from the first adherend or the second adherend side and before the temperature drops to the ambient temperature of the dismantling work environment (step S3A), wherein the easily dismantled adhesive sheet consists only of the adhesive layer.

[0156] In the second embodiment of the dismantling method according to the third embodiment, steps S1 and S2 are the same as in the first embodiment described above, but step S3A differs in the following respect: After heating the laminated structure from the side of the first adherend or the second adherend, while the temperature drops to the ambient temperature of the dismantling work environment, one of the first adherend or the second adherend is not separated from the easily dismantled adhesive sheet, and the other of the first adherend or the second adherend that was not separated from the easily dismantled adhesive sheet is separated from the easily dismantled adhesive sheet (step S3B).

[0157] The third embodiment of the dismantling method according to the third embodiment is similar to the first embodiment in that steps S1, S2, and S3A are the same steps, but the easily dismantled adhesive sheet comprises a base material and adhesive layers provided on both sides of the base material.

[0158] A fourth aspect of the dismantling method according to the third embodiment is similar to the second embodiment in terms of steps S1, S2, and S3B, but differs in that the easily dismantled adhesive sheet comprises a base material and adhesive layers provided on both sides of the base material.

[0159] The method for dismantling the laminated structure according to this embodiment will be described below with reference to the drawings. In the drawings, some parts are enlarged or reduced in size for the sake of clarity.

[0160] The following description will primarily focus on the differences between the laminated structures 200 and 220 according to the second embodiment, and redundant explanations will be omitted or simplified. Components similar to those in the laminated structures 200 and 220 according to the second embodiment will be denoted by the same reference numerals, and their explanations will be omitted or simplified. Furthermore, redundant explanations regarding the dismantling method according to this embodiment will be omitted or simplified.

[0161] [First and Second Embodiments] Figures 4A, 4B, 4C, 4D, and 4E show schematic diagrams illustrating an example of a method for dismantling a laminated structure according to this embodiment. Specifically, the schematic diagrams shown in Figures 4A to 4E illustrate an example of the first and second embodiments of the dismantling method according to this embodiment.

[0162] (Step S1) Step S1 is a step in which the laminated structure described in the second embodiment is prepared. In Figure 4A, the laminated structure 200 described in the first aspect of the second embodiment is prepared as the laminated structure to be dismantled. A specific example of the laminated structure 200 is as described above.

[0163] (Step S2) Step S2 is a step in which the laminated structure prepared in step S1 is heated. In Figure 4B, a hot plate 50 is used as a heating means for heating the laminated structure 200. As shown in Figure 4B, the heating surface 50A of the hot plate 50 is in contact with the surface (second main surface 42B) of the second adherend 42 of the laminated structure 200. With the heating surface 50A of the hot plate 50 in contact with the second main surface 42B of the second adherend 42, the laminated structure 200 is heated from the second adherend 42 side. Figure 4B shows that the laminated structure 200 is heated from the second adherend 42 side with the heating surface 50A of the hot plate 50 in contact with the second main surface 42B of the second adherend 42 in the laminated structure 200. However, it is not limited to this, and the laminated structure 200 may also be heated from the first adherend 41 side with the heating surface 50A of the hot plate 50 in contact with the first main surface 41A of the first adherend 41 in the laminated structure 200. From the viewpoint of dismantling workability, it is preferable to heat the laminated structure 200 from one side of the two adherends 40. If, in step S2, the laminated structure 200 is heated from the first adherend 41 side instead of the second adherend 42 side, then in steps S3A or S3B after step S2, the second adherend 42 will be replaced with the first adherend 41.

[0164] The heating conditions for heating the laminated structure 200 are not particularly limited. The heating conditions for heating the laminated structure 200 depend on the material of the adherend, but should be such that at least the second adherend 42 and the easily dismantled adhesive sheet 100 can be separated. The temperature of the hot plate 50 when heating the laminated structure 200 is not particularly limited, and may be, for example, 80°C or higher, 90°C or higher, 100°C or higher, or 110°C or higher. The upper limit of the temperature of the hot plate 50 when heating the laminated structure 200 is not particularly limited, and should be within a temperature range that allows at least the second adherend 42 and the easily dismantled adhesive sheet 100 to be separated and allows for the dismantling of the laminated structure 200. The time for heating the laminated structure 200 is not particularly limited, and may be, for example, 5 seconds or more, 10 seconds or more, 30 seconds or more, or 1 minute or more. The time for heating the laminated structure 200 is not particularly limited and may be, for example, 1 hour or less, 30 minutes or less, 10 minutes or less, or 5 minutes or less.

[0165] In Figure 4B, a hot plate 50 is used as a heating means for heating the laminated structure 200, but the heating means is not particularly limited as long as it is a heating means that can heat the laminated structure 200 by contacting it. In addition to the hot plate 50, various contact heating devices such as surface heaters, heat blocks, and hot rolls can be used as heating means. From the viewpoint of ease of dismantling, it is preferable to use a hot plate 50 as the heating means.

[0166] (Step S3A) Step S3A is a step in dismantling the laminated structure 200 by separating the two adherends 40 (the first adherend 41 and the second adherend 42) from the easily dismantled adhesive sheet 100 while the laminated structure 200 is heated in step S2 and before the temperature drops to the ambient temperature of the dismantling work environment. For example, depending on the form of the laminated structure 200, it is possible for the two adherends 40 to be separated from the easily dismantled adhesive sheet 100 at the same time, but from the viewpoint of ease of dismantling the laminated structure 200, it is preferable to separate them sequentially from the easily dismantled adhesive sheet 100. Specifically, one adherend 40 is separated from the easily dismantled adhesive sheet 100, and then the other adherend 40 is separated from the easily dismantled adhesive sheet 100.

[0167] As shown in Figure 4C, after heating the laminated structure 200 from the second adherend 42 side is complete, the hot plate 50 is pulled away from the second adherend 42. Then, after pulling away the hot plate 50, as shown in Figure 4D, the second adherend 42 and the easily dismantled adhesive sheet 100 are separated by a step (step S3A-1) to separate the second adherend 42 and the easily dismantled adhesive sheet 100 that the hot plate 50 was in contact with, and as shown in Figure 4E, the first adherend 41 and the easily dismantled adhesive sheet 100 that the hot plate 50 was not in contact with are separated by a step (step S3A-2). Through these steps, the second adherend 42, the easily dismantled adhesive sheet 100, and the first adherend 41 are separated sequentially. The laminated structure 200 is dismantled through these steps. The separation means for separating the two adherends 40 and the easily dismantled adhesive sheet 100 can be a separation means such as a peeling device (not shown). The peeling device is not particularly limited as long as it can separate the adherend 40 from the easily disassembled adhesive sheet 100. Furthermore, it is not limited to this, and the two adherends 40 and the easily disassembled adhesive sheet 100 may be separated by hand without using a peeling device. When the laminated structure 200 is disassembled in the state shown in Figure 4E, it becomes a diagram illustrating an example of the first aspect of the disassembly method according to this embodiment.

[0168] After heating the laminated structure 200 and removing the hot plate 50 from the laminated structure 200, the temperature of the heated laminated structure 200 decreases over time. The two adherends 40 and the easily dismantled adhesive sheet 100 are separated before the temperature drops to the ambient temperature of the dismantling work environment. The ambient temperature of the dismantling work environment is not particularly limited, but for example, it may be 40°C. From the viewpoint of easily dismantling the laminated structure 200, it is preferable to separate the two adherends 40 and the easily dismantled adhesive sheet 100 while the temperature of the heated laminated structure 200 is still small. The temperature at which the two adherends 40 and the easily dismantled adhesive sheet 100 are separated is preferably higher than 40°C, for example, as the temperature of the second adherend 42 that was in contact with the hot plate 50, and may be 60°C or higher, 80°C or higher, 90°C or higher, 100°C or higher, or 110°C or higher.

[0169] The laminated structure 200 can be separated into the first adherend 41, the easily disassembled adhesive sheet 100, and the second adherend 42 by both steps S3A-1 and S3A-2. Because the laminated structure 200 includes an easily disassembled adhesive sheet 100 consisting only of an adhesive layer 10, the adherend 40 and the adhesive layer 10 tend to separate more easily in step S3A-1 than in step S3A-2.

[0170] (Step S3B) Step S3B differs from step S3A in that the first adherend 41 is not separated from the easily dismantled adhesive sheet 100, and the first adherend 41 is left attached to the easily dismantled adhesive sheet 100. That is, step S3B completes the dismantling of the laminated structure 200 in the state shown in Figure 4D. Other specific examples are as described in step S3A. When the dismantling of the laminated structure 200 is completed in the state shown in Figure 4D, the figure illustrates an example of a second embodiment of the dismantling method according to this embodiment.

[0171] [Third and Fourth Embodiments] Figures 5A, 5B, 5C, and 5D show schematic diagrams illustrating other examples of the dismantling method for the laminated structure according to this embodiment. Specifically, Figures 5A to 5D are schematic diagrams illustrating examples of the third and fourth embodiments of the dismantling method according to this embodiment.

[0172] In Figures 5A, 5B, 5C, and 5D, the laminated structure 220 described in the third aspect of the second embodiment is disassembled instead of the laminated structure 200 shown in Figures 4A, 4B, 4D, and 4E, respectively. Figure 5A represents the aforementioned step S1, in which the laminated structure 220 is prepared as the object to be disassembled. A specific example of the laminated structure 220 is as described above. Figure 5B represents the aforementioned step S2, which is as described in Figure 4B, except that the laminated structure 220 is heated by the hot plate 50. Figures 5C and 5D represent the aforementioned step S3A, in which the two adherends 40 and the easily disassembled adhesive sheet 120 of the laminated structure 220 are separated. As described in Figures 4D and 4E, the second adherend 42, the easily disassembled adhesive sheet 120, and the first adherend 41 are sequentially separated by the same process as the aforementioned steps S3A-1 and S3A-2. When the laminated structure 220 is dismantled in the state shown in Figure 5D, it is a diagram illustrating an example of a third aspect of the dismantling method according to this embodiment. When the dismantling of the laminated structure 220 is completed in the state shown in Figure 5C, it is a diagram illustrating an example of a fourth aspect of the dismantling method according to this embodiment, and as explained in step S3B, the first adherend 41 of the laminated structure 220 is left on the easily dismantled adhesive sheet 120, and the second adherend 42 is separated from the easily dismantled adhesive sheet 120.

[0173] As described above, the laminated structure 220 can be separated from the first adherend 41, the easily disassembled adhesive sheet 120, and the second adherend 42 by the same process as in both steps S3A-1 and S3A-2. Because the laminated structure 220 includes an easily disassembled adhesive sheet 120 equipped with a base material 30, the base material 30 supports the adhesive layer 10 (first adhesive layer 11 and second adhesive layer 12), making it less likely for the adhesive layer to break. In other words, in step S3A-1, the second adhesive layer 12 of the laminated structure 220 and the second adherend 42 are easier to separate than when separating the adhesive layer 10 of the laminated structure 200 and the second adherend 42, and in step S3A-2, the first adhesive layer 11 of the laminated structure 220 and the first adherend 41 are easier to separate than when separating the adhesive layer 10 of the laminated structure 200 and the first adherend 41. For this reason, the laminated structure 220, which includes an easily disassembled adhesive sheet 120 having a base material 30, tends to be superior in terms of ease of disassembly compared to the laminated structure 200.

[0174] [Fifth and Sixth Embodiments] Next, the fifth and sixth embodiments of this embodiment will be described. In the fifth embodiment of this embodiment, the process is the same as in the first embodiment except that process S2 is different, and in the sixth embodiment, the process is the same as in the second embodiment except that process S2 is different. In the fifth and sixth embodiments of this embodiment, the process of heating the laminated structure includes a process (process S2A) of heating the laminated structure by leaving the laminated structure in a high-temperature environment.

[0175] Here, we will refer again to Figures 4A to 4E. In the fifth and sixth embodiments of this embodiment, instead of the hot plate 50 shown in Figure 4B, a high-temperature environment is created by a heating means (not shown), and the laminated structure 200 is heated by placing it in the created high-temperature environment. The rest is as described in Figures 4A to 4E. The high-temperature environment is created, for example, by heating a gas to a predetermined temperature using a heating means such as a heater, and circulating the heated gas into the high-temperature chamber using a blower or the like. Then, by placing the laminated structure 200 in the high-temperature chamber, the entire laminated structure 200 is heated and the laminated structure 200 is disassembled. Specific examples of the temperature in the high-temperature chamber and the heating time of the laminated structure 200 can be found in the specific examples of the heating temperature and heating time described in the first to fourth embodiments. In the fifth and sixth embodiments of this embodiment, disassembly can be performed as described in the first and second embodiments.

[0176] [Seventh and Eighth Embodiments] Next, the seventh and eighth embodiments of this embodiment will be described. In the seventh and eighth embodiments of this embodiment, the laminated structure is the same as in the fifth and sixth embodiments, except that it comprises a base material and adhesive layers provided on both sides of the base material.

[0177] Refer again to Figures 5A to 5D. Similar to the fifth and sixth embodiments, instead of the hot plate 50 shown in Figure 5B, a heating means (not shown) is used to create a high-temperature environment, and the laminated structure 220 is heated by placing it in the created high-temperature environment. Everything else is as described in Figures 5A to 5D. The heating means and heating conditions are the same as in the specific examples described in the fifth and sixth embodiments.

[0178] In the seventh and eighth embodiments of this embodiment, the parts can be disassembled as described in the third and fourth embodiments.

[0179] [Ninth and Tenth Embodiments] Next, the ninth and tenth embodiments of this embodiment will be described. The ninth embodiment of this embodiment has the same steps as the first embodiment, except that step S2 is different from that of the first embodiment, and the tenth embodiment has the same steps as the second embodiment, except that step S2 is different from that of the second embodiment. In the ninth and tenth embodiments of this embodiment, the step of heating the laminated structure has a step (step S2B) of heating the laminated structure by bringing a heating medium into contact with at least one of the first adherend and the second adherend.

[0180] Here again, we refer to Figures 4A to 4E. In the ninth and tenth embodiments of this embodiment, instead of the hot plate 50 shown in Figure 4B, the heating means is not brought into contact with the adherend, and a heating medium (not shown) is brought into contact with either one of the adherends 40 of the first adherend 41 or the second adherend 42, or with both adherends 40 of the first adherend 41 and the second adherend 42. For example, the laminated structure 200 may be heated from the surface of at least one of the adherends 40 on the first adherend 41 side and the second adherend 42 side. Otherwise, it is as described in Figures 4A to 4E. Examples of heating mediums include hot water, hot oil, and hot air at a predetermined temperature. Contact with the heating medium can be, for example, by spraying hot water or hot oil, or by immersing in hot water or hot oil. Alternatively, contact with the heating medium can also be, for example, by blowing hot air. Then, the laminated structure 200 is heated by contact with the heating medium, causing the laminated structure 200 to disintegrate. Specific examples of the temperature of the heating medium and the heating time of the laminated structure 200 are given by the specific examples of the heating temperature and heating time described in the first to fourth embodiments.

[0181] [Eleventh and Twelfth Embodiments] Next, the eleventh and twelfth embodiments of this embodiment will be described. In the eleventh and twelfth embodiments of this embodiment, the laminated structure is the same as in the ninth and tenth embodiments, except that it comprises a base material and adhesive layers provided on both sides of the base material.

[0182] Referring again to Figures 5A to 5D, similar to the ninth and tenth embodiments, instead of the hot plate 50 shown in Figure 5B, the heating means is not brought into contact with the object to be attached, and a heating medium (not shown) is brought into contact with either the first object 41 or the second object 42, or with both objects 40 of the first object 41 and the second object 42. Everything else is as described in Figures 5A to 5D. The heating medium and heating conditions are the same as those described in the specific examples in the ninth and tenth embodiments.

[0183] In the ninth to twelfth embodiments of this embodiment, the laminated structure 200 or the laminated structure 220 can be disassembled in the same manner as in the first to fourth embodiments of this embodiment. In addition, in some cases, the eleventh and twelfth embodiments of this embodiment can also disassemble the laminated structure 220 in the manner described in the seventh and eighth embodiments of this embodiment.

[0184] The dismantling methods for the laminated structure 200 and the laminated structure 220 according to this embodiment can be applied to the dismantling of components used in at least a part of large products such as home appliances. The dismantling methods for the laminated structure 200 and the laminated structure 220 according to this embodiment can also be applied to the dismantling of components used in at least a part of small products such as electronic devices.

[0185] The above describes an example of a method for dismantling a laminated structure according to this embodiment with reference to the drawings, but the method for dismantling a laminated structure according to this embodiment is not limited thereto. Various forms can be adopted for the method for dismantling a laminated structure according to this embodiment, as long as it has the above configuration. For example, in the first to fourth embodiments of this embodiment, heating of the laminated structure is not limited to heating from only one adherend side to separate the heated adherend from the easily dismantled adhesive sheet, but may also be done by heating from one adherend side to separate the heated adherend from the easily dismantled adhesive sheet, and then separately heating from the other adherend side that has not been separated to separate the separately heated adherend from the easily dismantled adhesive sheet. However, in the first to fourth embodiments of the method for dismantling a laminated structure according to this embodiment, the laminated structure is not heated from both adherend sides at the same time before separating the adherend and the easily dismantled adhesive sheet.

[0186] Furthermore, the fifth to twelfth embodiments of the method for dismantling the laminated structure according to this embodiment can adopt various forms as long as they have the above-described configuration.

[0187] (Effects of the Third Embodiment) According to this embodiment, the following effects can be achieved. (1C): Since the laminated structure 200 or laminated structure 220 made using the easily dismantled adhesive sheet 100 or the easily dismantled adhesive sheet 120 is equipped with the adhesive layer 10 described in the first embodiment, when the laminated structure 200 or laminated structure 220 is dismantled, adhesive residue on the two adherends 40 (first adherend 41 and second adherend 42) is suppressed after separating the easily dismantled adhesive sheet 100 or the easily dismantled adhesive sheet 120. (2C): When the laminated structure 200 or laminated structure 220 is dismantled, even if only one of the two adherends 40 (first adherend 41 or second adherend 42) is separated, adhesive residue on the separated adherend 40 is suppressed. (3C): The laminated structure 220 has an easily disassembled adhesive sheet 120 equipped with a base material 30, so that the base material 30 supports the adhesive layer 10, making it difficult for the adhesive layer 10 to break and easy to separate the adhesive layer 10 from the adherend 40. For this reason, compared to disassembling a laminated structure 200 which has an easily disassembled adhesive sheet 100 composed only of an adhesive layer 10 without a base material 30, the laminated structure 220 is easier to disassemble and reuse. (4C): The laminated structure 200 and the laminated structure 220 are equipped with the adhesive layer 10 described in the first embodiment. Therefore, the easily disassembled adhesive sheet 100 after being disassembled from the laminated structure 200 and the easily disassembled adhesive sheet 120 after being disassembled from the laminated structure 220 can be attached and detached repeatedly and thus can be used multiple times.

[0188] [Fourth Embodiment] <Method of Use> The fourth embodiment is a method of using the easily dismantled adhesive sheet. The method of use according to this embodiment includes the steps of: attaching the easily dismantled adhesive sheet according to the first embodiment to an adherend comprising at least one material selected from the group consisting of metal, glass, and resin (step U1); separating the adherend and the easily dismantled adhesive sheet (step U2); and, after the separation step, attaching the easily dismantled adhesive sheet to the adherend, or to another adherend different from the adherend (step U3). Since the method of use according to this embodiment uses the easily dismantled adhesive sheet according to the first embodiment, after going through steps U1 to U3, steps U2 and U3 can be repeated again. In the method of use according to this embodiment, steps U2 and U3 can be repeated at least five times.

[0189] The method of use according to this embodiment involves, first, in step U1, attaching the easily disassembled adhesive sheet according to the first embodiment to the adherend under normal temperature conditions. This results in an adhesive body in which the easily disassembled adhesive sheet is attached to the adherend. The adhesive body may also be a laminated structure according to the second embodiment. The ambient temperature when attaching the easily disassembled adhesive sheet according to the first embodiment to the adherend is not limited to normal temperature conditions, but may also be higher than normal temperature conditions or high temperature conditions. Examples of higher temperature conditions include 60°C or higher, and examples of high temperature conditions include 80°C or higher. Methods for attaching the easily disassembled adhesive sheet according to the first embodiment to the adherend include attaching it using an attachment device, attaching it using an attachment jig, and attaching it by hand without using an attachment device or jig.

[0190] Next, in step U2, the adhesive body prepared by attaching the easily disassembled adhesive sheet to the adherend is heated to a high temperature (for example, 80°C or higher). Then, in the high-temperature environment, the adherend and the easily disassembled adhesive sheet of the adhesive body are separated. The method for heating the adhesive body to a high temperature may be, for example, the same method as described in the disassembly method of the third embodiment. The method for separating the adherend and the easily disassembled adhesive sheet may be the same method as described in the disassembly method of the third embodiment. If, in step U1, a laminated structure according to the second embodiment is prepared as the adhesive body, then in step U2, the adherend and the easily disassembled adhesive sheet can be separated by the same method as described in the disassembly method of the laminated structure according to the third embodiment.

[0191] Next, in step U3, the easily disassembled adhesive sheet separated in step U2 is attached to the same adherend as the adherend separated in step U2, or to a different adherend than the adherend separated in step U2. The different adherend than the adherend separated in step U2 may be an adherend with the same configuration using the same material, or an adherend with a different configuration using different materials. In this way, the easily disassembled adhesive sheet separated from the adherend in step U2 can be reattached. The method for reattaching the easily disassembled adhesive sheet can be the same as in step U1. If, for example, a laminated structure according to the second embodiment is manufactured in step U1, then in step U3, for example, the easily disassembled adhesive sheet obtained by separating it using the disassembly method for the laminated structure according to the third embodiment can be reattached to the adherend obtained by separating it using the said disassembly method. Alternatively, for example, the easily disassembled adhesive sheet obtained by separating it using the disassembly method for the laminated structure according to the third embodiment can be reattached to a different adherend than the adherend obtained by separating it using the said disassembly method.

[0192] In the method of use according to this embodiment, if a laminated structure according to the second embodiment is manufactured in step U1, the easily disassembled adhesive sheet obtained by separating it in step U2 using the disassembly method of the laminated structure according to the third embodiment can also be subjected to the repetition of steps U2 and U3 at least five times.

[0193] (Effects of the Fourth Embodiment) According to this embodiment, the effects described in (1A) to (6A) of the first embodiment, (1B) to (2B) of the second embodiment, and (1C) to (4C) of the third embodiment can be achieved.

[0194] [Modifications of Embodiments] The present invention is not limited to the embodiments described above, and any modifications or improvements that can achieve the objectives of the present invention are included in the present invention.

[0195] The present invention will be described in more detail below with reference to examples. The present invention is not limited to these examples.

[0196] [Preparation of Adhesive Sheets] Adhesive sheets for each example and comparative example were prepared according to the following procedure. In the following examples and comparative examples, unless otherwise specified, parts by mass are parts by mass on a solid content basis.

[0197] <Example 1> (a1) In a reaction vessel for the synthesis of silyl group-containing resins, 206 parts by mass of N-aminoethyl-γ-aminopropylmethyldimethoxysilane and 172 parts by mass of methyl acrylate were reacted under a nitrogen atmosphere with stirring and heating conditions at 80°C for 10 hours to obtain a silylating agent.

[0198] In a separate reaction vessel, 1,000 parts by mass of polyoxypropylene diol (AGC Inc., PMLS4015, molecular weight 15,000), 24.6 parts by mass of isophorone diisocyanate (NCO / OH ratio = 1.7), and 0.05 parts by mass of dibutyltin dilaurate were reacted at 85°C for 7 hours under a nitrogen atmosphere with stirring, to obtain a urethane prepolymer in which the main chain is primarily polyoxypropylene and in which urethane bonds have been introduced into the main chain.

[0199] To 1000 parts by mass of the urethane prepolymer obtained above, 42.1 parts by mass of the silylation agent obtained above was added, and the mixture was stirred and reacted at 80°C for 1 hour under a nitrogen atmosphere to obtain a silyl group-containing resin. The absorption of the isocyanate group by IR was 2265 cm⁻¹. －１The progress of the reaction was confirmed by the degree of disappearance of the ) . The obtained silyl group-containing resin has two methoxy groups as hydrolyzable silyl groups at both ends of the main chain, the main body of the main chain is polyoxypropylene, and a urethane bond has been introduced into the main chain. The structure of the terminal portion of the silyl group-containing resin with hydrolyzable silyl groups is represented by the following formula (11A). * in the following formula (11A) indicates the bond position.

[0200]

[0201] (a2) Preparation of the adhesive composition A fluorine catalyst solution was prepared by dissolving 1 part by mass of boron trifluoride monoethylamine complex (containing 59% by mass as boron trifluoride) in 9 parts by mass of 3-aminopropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM903). 100 parts by mass of the silyl group-containing resin obtained above and 42 parts by mass of terpene phenol-based tackifying resin (manufactured by Yasuhara Chemical Co., Ltd., YS Polystar T-130, softening point 130°C) were mixed and stirred until nearly homogeneous to obtain a mixture. Then, 1 part by mass of the fluorine catalyst solution prepared above was mixed into this mixture and stirred until nearly homogeneous to prepare the adhesive composition.

[0202] (a3) Preparation of easily disassembled adhesive sheet The adhesive composition prepared above was melt-coated using a hot-melt coater to the release surface of the first release liner and the release surface of the second release liner, respectively, to form a first adhesive layer with a thickness of 50 μm on the release surface of the first release liner to obtain a release liner with a first adhesive layer, and a second adhesive layer with a thickness of 50 μm was formed on the release surface of the second release liner to obtain a release liner with a second adhesive layer. Subsequently, a polyethylene terephthalate (PET) film (Toray Industries, Inc., Lumirror T60, 50 μm thick) as a base material was laminated to the adhesive surface of the first adhesive layer formed on the first release liner. As a result, a single-sided adhesive sheet with a release liner and base material was obtained in which the first release liner, the first adhesive layer, and the base material were laminated in this order. The adhesive surface of the release liner with the second adhesive layer was laminated to the side of the base material of the obtained single-sided adhesive sheet with a release liner and base material to which the first adhesive layer was not attached. This resulted in a double-sided adhesive sheet with a release liner and a substrate sandwiched between two release liners. The obtained double-sided adhesive sheet with a release liner and substrate was cured for 7 days under conditions of 40°C and 80% RH to produce a double-sided adhesive sheet that is easy to disassemble, in which the first release liner, the first adhesive (thickness: 50 μm), the PET film (substrate), the second adhesive (thickness: 50 μm), and the second release liner were laminated in this order. The silyl group-containing resin contained in the two adhesive layers of the obtained double-sided adhesive sheet was pre-moisturized.

[0203] <Example 2> In the preparation of the adhesive composition (a2) of Example 1, the mixture was changed to a mixture obtained by mixing 100 parts by mass of a silyl group-containing resin, 42 parts by mass of a terpene phenol-based tackifying resin (Yasuhara Chemical Co., Ltd., YS Polystar T-130), and 48 parts by mass of an acrylic-based tackifying resin (Seiko PMC Co., Ltd., Hyros ATF-2377, weight-average molecular weight Mw: 3200, softening point 135°C), and stirring until it became nearly homogeneous. Otherwise, a double-sided adhesive sheet was prepared as an easily dismantled adhesive sheet in the same manner as in Example 1.

[0204] <Comparative Example 1> (b1) Preparation of Adhesive Composition An acrylic resin was obtained by polymerizing 90 parts by mass of butyl acrylate, 1 part by mass of vinyl acetate, and 9 parts by mass of acrylic acid. The weight-average molecular weight Mw, measured using gel permeation chromatography (GPC) (GPC measurement), was 500,000 (500,000). An adhesive composition was prepared by mixing 100 parts by mass of the obtained acrylic resin with 0.05 parts by mass of epoxy crosslinking agent (manufactured by Mitsubishi Gas Chemical Company, Inc., TETRAD-C) and diluting with toluene (solvent).

[0205] (b2) Preparation of adhesive sheet A double-sided adhesive sheet was obtained in the same manner as in Example 1, except that, in the preparation of the easily disassembled adhesive sheet (a3) ​​in Example 1, the adhesive composition prepared with the above (b1) adhesive composition was applied to the peel-treated surface of the first release liner using a knife coater so that the thickness after drying was 20 μm, thereby forming an adhesive layer.

[0206] <Comparative Example 2> A double-sided adhesive sheet was obtained in the same manner as in Comparative Example 1, except that the epoxy crosslinking agent was changed to 0.25 parts by mass in the preparation of the adhesive composition (b1) of Comparative Example 1.

[0207] [Evaluation of Adhesive Sheets] Measurements or evaluations of the adhesive sheets prepared in each of the above examples and comparative examples were performed by the following methods.

[0208] [Room Temperature Adhesion: SUS Plate] In accordance with JIS Z0237:2022, the adhesive strength was measured by peeling the adhesive sheet from the stainless steel test plate at 180°. Specifically, the release liner and single-sided adhesive sheet with substrate, obtained in each example and comparative example, before the adhesive layer of the second adhesive layer of the release liner was attached to the substrate, were cured for 7 days under conditions of 40°C and 80% RH to be used as a sample for the "Room Temperature Adhesion: SUS Plate" test. This sample was cut to a width of 25 mm, the first release liner was peeled off to expose the first adhesive layer, and the adhesive surface of the first adhesive layer was attached to a SUS304 stainless steel plate (SUS304 steel plate), and pressed once back and forth with a roller with a mass of 2000 g. Then, after standing for 20 minutes in an environment of 23°C and 50% RH, the sample was peeled off a SUS304 steel plate at a rate of 300 mm / min at a 180° angle in the same environment, and the room-temperature adhesive strength was measured.

[0209] [High-Temperature Adhesion: SUS Plate] Following the same procedure as for "Room Temperature Adhesion: SUS Plate," the aforementioned single-sided adhesive sheet was cured for 7 days under conditions of 40°C and 80% RH to prepare a sample for the "High-Temperature Adhesion: SUS Plate" test. This sample was cut to a width of 25 mm, the first release liner was peeled off to expose the first adhesive layer, and the adhesive surface of the first adhesive layer was attached to a SUS304 steel plate. It was then pressed back and forth once with a roller weighing 2000 g. After standing in a 100°C environment for 20 minutes, the sample was peeled off from the SUS304 steel plate at a 180° angle at a peeling speed of 300 mm / min in the same environment, and the high-temperature adhesion was measured.

[0210] [Room Temperature Adhesion: Glass Plate (Ps0)] In accordance with JIS Z0237:2022, the adhesive strength was measured by peeling the adhesive sheet off the substrate at a 180° angle. However, for "Room Temperature Adhesion: Glass Plate," the stainless steel plate was replaced with a glass plate, and the adhesive strength to the glass plate was measured. Specifically, the release liner and single-sided adhesive sheet with substrate, obtained when preparing each example and comparative example, before attaching the adhesive layer of the second adhesive layer to the substrate, were cured for 7 days under conditions of 40°C and 80% RH to prepare the sample for the "Room Temperature Adhesion: Glass Plate" test. This sample was cut to a width of 25 mm, the first release liner was peeled off to expose the first adhesive layer, and the adhesive surface of the first adhesive layer was attached to a 3 mm glass plate and pressed once back and forth with a roller with a mass of 2000 g. The test piece prepared here was designated as the first test piece. Then, after standing for 30 minutes in an environment of 23°C and 50% RH, the sample was peeled off the glass plate at a rate of 300 mm / min at a 180° angle in the same environment, and the room-temperature adhesive strength was measured. The measurement of the room-temperature adhesive strength measured on the first test piece corresponds to the procedure described in (S1-1) to (S1-3) above. The room-temperature adhesive strength measured on the first test piece is denoted as Ps0.

[0211] [High-temperature adhesive strength: Glass plate (Ps1-Ps5)] Following the same procedure as for "Room temperature adhesive strength: Glass plate" above, the aforementioned single-sided adhesive sheet was prepared separately. The prepared single-sided adhesive sheet was cured for 7 days under conditions of 40°C and 80% RH to prepare a sample for the "High-temperature adhesive strength: Glass plate" test. This sample was cut to a width of 25 mm, the first release liner was peeled off to expose the first adhesive layer, and the adhesive side of the first adhesive layer was attached to the glass plate. It was then pressed back and forth once with a roller weighing 2000 g. The test piece prepared here was designated as the second test piece. The second test piece was left to stand for 30 minutes in an environment of 120°C, and in the same environment, the sample was peeled off from the glass plate at a rate of 300 mm / min at a 180° angle to measure the high-temperature adhesive strength.

[0212] The "room temperature adhesive strength: glass plate" measured above was defined as the high-temperature adhesive strength for the first cycle. After measuring the high-temperature adhesive strength for the first cycle, the glass plate and single-sided adhesive sheet, which had been peeled off during the measurement of the high-temperature adhesive strength in the first cycle, were left to cool to 23°C. After cooling to 23°C, the high-temperature adhesive strength for the second cycle was measured using the glass plate and single-sided adhesive sheet in the same manner as described above for the "high-temperature adhesive strength: glass plate". After measuring the high-temperature adhesive strength for the second cycle, the glass plate and single-sided adhesive sheet, which had been peeled off during the measurement of the high-temperature adhesive strength in the first cycle, were left to cool to 23°C. After cooling to 23°C, the high-temperature adhesive strength was measured again using the glass plate and single-sided adhesive sheet in the same manner as described above, and this process was repeated to measure the high-temperature adhesive strength for the third, fourth, and fifth cycles. In this manner, the high-temperature adhesive strength of the second test specimen was measured multiple times from the first to the fifth cycle. These multiple measurements of high-temperature adhesive strength correspond to the procedures described in (S2-1) to (S2-4) above. The high-temperature adhesive strength measured in the first cycle on the second test specimen is designated as Ps1, the high-temperature adhesive strength measured in the second cycle is designated as Ps2, and similarly, the high-temperature adhesive strengths measured in the third to fifth cycles are designated as Ps3, Ps4, and Ps5, respectively.

[0213] [High-temperature adhesive strength: Room temperature adhesive strength (Ps6) after passing through glass plates (Ps1 to Ps5)] After measuring the high-temperature adhesive strength in the fifth cycle as described above, the glass plate and single-sided adhesive sheet that were peeled off during the measurement of the high-temperature adhesive strength in the fifth cycle were left to stand until cooled to 23°C. After cooling to 23°C, a test specimen was prepared using the glass plate and single-sided adhesive sheet in the same procedure as for "Room temperature adhesive strength: Glass plate" described above. The test specimen prepared here was designated as the third test specimen. The room temperature adhesive strength of the third test specimen was then measured as the room temperature adhesive strength after five measurements of "Room temperature adhesive strength: Glass plate". The measurement of room temperature adhesive strength on the third test specimen corresponds to the procedure described above in (S3-1) to (S3-3). The room temperature adhesive strength measured on the third test specimen is designated as Ps6.

[0214] [Adhesion retention rate: Glass plate] The adhesion retention rate (unit: %) was calculated for the room temperature adhesion Ps6 ((Ps6 / Ps0) × 100) measured on the third test piece, relative to the room temperature adhesion Ps0 measured on the first test piece. The adhesion retention rate is expressed as (Ps6) / (Ps0) in the table.

[0215] [Ratio of high-temperature adhesive strength to room-temperature adhesive strength: glass plate] When the room-temperature adhesive strength measured on the first test piece above is taken as Ps0 and the first high-temperature adhesive strength Ps1 measured on the second test piece above is taken as Ps1, the ratio of Ps1 to Ps0 (Ps1 / Ps0) was calculated. The ratio of high-temperature adhesive strength to room-temperature adhesive strength is denoted as (Ps1) / (Ps0) in the table.

[0216] [Easy Disassembly] The double-sided adhesive sheets prepared in each example and comparative example were cut to 7 cm x 5 cm. One release liner (first release liner) was peeled off, and the adhesive surface of the exposed adhesive layer (first adhesive layer) was attached to a glass plate measuring 7 cm x 14 cm x 3 mm. Subsequently, the other release liner (second release liner) was peeled off, and another glass plate was attached to the adhesive surface of the exposed adhesive layer (second adhesive layer) to create a laminated structure, which was used as a sample for the easy disassembly test. The obtained samples were left to stand for 24 hours under conditions of 23°C and 50% RH, and then placed on a hot plate heated to 120°C and heated for 2 minutes. After that, the glass plate attached to the adhesive layer on the side that was in contact with the hot plate was peeled off by hand, and then the adhesive layer was peeled off by hand from the glass plate on the side that was not in contact with the hot plate. The ease of disassembly was evaluated according to the evaluation criteria below. <Evaluation Criteria> A: The glass can be easily peeled off the double-sided adhesive sheet by hand. F: The glass cannot be peeled off the double-sided adhesive sheet by hand.

[0217] [Adhesive Residue] After the ease of disassembly evaluation, the adhesive layer was visually checked on the side of the glass plate that was in contact with the hot plate where the double-sided adhesive sheet was attached (the adhesive surface), and the adhesive residue was evaluated according to the following evaluation criteria. <Evaluation Criteria> A: No adhesive remains on the adhesive surface of the glass plate, and no adhesive residue occurs. F: Adhesive remains on the adhesive surface of the glass plate, and adhesive residue occurs.

[0218]

[0219] When the double-sided adhesive sheet of Comparative Example 1 was used, the adhesive strength at room temperature (SUS plate) and the adhesive strength at room temperature (glass plate, (Ps0)) were equivalent to those of Example 1, but the high-temperature adhesive strength (SUS plate) was higher than that of the double-sided adhesive sheets of each example. Furthermore, the high-temperature adhesive strength (glass plate, (Ps0)) was equivalent to that of Example 2, but the high-temperature adhesive strength in the first cycle was lower than that of the double-sided adhesive strength of each example due to cohesive failure. In a test of the ease of disassembly of a laminated structure made by joining two glass plates using the double-sided adhesive sheet of Comparative Example 1, cohesive failure occurred in the adhesive layer attached to the glass plate, resulting in adhesive residue on the glass plate. In addition, because cohesive failure occurred in the adhesive layer of the double-sided adhesive sheet of Comparative Example 1, the double-sided adhesive sheet of Comparative Example 1 could not be reattached to the glass plate, which was the adherend, and repeated attachment and detachment to the adherend was not possible.

[0220] The high-temperature adhesive strength (SUS plate) of Comparative Example 2 was lower than that of Example 1, but was almost the same, and lower than that of Example 2. In a test of the ease of disassembly of a laminated structure made by joining two glass plates using the double-sided adhesive sheet of Comparative Example 2, peeling was possible at the interface between the adhesive layer of the double-sided adhesive sheet and the glass plate, and no adhesive residue was left on the glass plate. However, the room-temperature adhesive strength (SUS plate) and room-temperature adhesive strength (glass plate, (Ps0)) when using the double-sided adhesive sheet of Comparative Example 2 were significantly lower than those of Example 1 and Example 2. As a result, the double-sided adhesive sheet of Comparative Example 2 peeled off easily from the adherends, the SUS plate and the glass plate, respectively.

[0221] In contrast, when the double-sided adhesive sheet of Example 1 or Example 2 was used as the easily disassembled adhesive sheet, it exhibited excellent adhesive strength at room temperature. Furthermore, in an easy disassembly test of a laminated structure made by joining two glass plates using the double-sided adhesive sheet of Example 1 or Example 2, peeling was possible at the interface between the adhesive layer of the double-sided adhesive sheet and the glass plate, and no adhesive residue was left on the glass plate. Therefore, it can be seen that the double-sided adhesive sheets of each example, which have an adhesive layer containing a silyl group-containing resin having hydrolyzable silyl groups with a specific structure and a terpene phenol-based tackifying resin, maintain high adhesive strength at room temperature to the SUS plate or glass plate as the adherend, while suppressing adhesive residue when disassembling the laminated structure equipped with the easily disassembled adhesive sheet, compared to the adhesive sheets of each comparative example which have an acrylic adhesive layer. Moreover, since the double-sided adhesive sheet of Example 1 or Example 2 did not experience cohesive failure in the adhesive layer, it can be seen that it is possible to repeatedly attach it to the glass plate (the adherend) at room temperature and separate it at high temperature at least five times. Furthermore, the double-sided adhesive sheet used as an easily dismantled adhesive sheet in Example 1 or Example 2 exhibits high adhesive strength at room temperature and low adhesive strength at high temperatures, indicating that the usage environment can be selected according to the desired adhesive strength.

[0222] From the results above, it was confirmed that the easily disassembled adhesive sheets of each embodiment maintain high adhesive strength to the adherend at room temperature, suppress adhesive residue when separated from the adherend, and can be used multiple times even after separation from the adherend by reducing the adhesive strength of the adhesive layer at high temperatures.

[0223] 10...Adhesive layer, 10A...First main surface (adhesive layer), 10B...Second main surface (adhesive layer), 11...First adhesive layer, 11A...First main surface (first adhesive layer), 11B...Second main surface (first adhesive layer), 12...Second adhesive layer, 12A...First main surface (second adhesive layer), 12B...Second main surface (second adhesive layer), 20...Release liner, 21...First release liner, 21B...Second main surface (first release liner), 22...Second release liner, 22A...First main surface (second Release liner), 30...Substrate, 30A...First main surface (substrate), 30B...Second main surface (substrate), 40...Adhesion, 41...First adherend, 41A...First main surface (first adherend), 41B...Second main surface (first adherend), 42...Second adherend, 42A...First main surface (second adherend), 42B...Second main surface (second adherend), 50...Hot plate (example of heating means), 50A...Heating surface, 100, 110, 120...Easily dismantled adhesive sheet, 200, 220...Laminated structure.

Claims

1. An easily disassembled adhesive sheet comprising an adhesive layer containing a moisture-cured product of a silyl group-containing resin and a terpene phenol-based tackifying resin, wherein the silyl group-containing resin has a polyoxyalkylene structure in its main chain, and has both urethane bonds and urea bonds in a part of the main chain or in a side chain, or has either one of the urethane bonds and urea bonds, and has hydrolyzable silyl groups represented by the following formula (1) at both ends of the main chain, and is capable of repeated attachment and detachment from an adherend. (In the above formula (1), X １ and X ２ Each of these is independently a hydroxyl group or an alkoxy group, R is an alkyl group having 1 to 20 carbon atoms, and * indicates the bond position.

2. An easily dismantled adhesive sheet according to claim 1, wherein the content of the terpene phenol-based tackifying resin is 20 parts by mass or more and 100 parts by mass or less per 100 parts by mass of the silyl group-containing resin.

3. An easily dismantled adhesive sheet according to claim 1 or claim 2, wherein the adhesive layer further comprises an acrylic tackifying resin, and the content of the acrylic tackifying resin is 1 part by mass or more and 100 parts by mass or less per 100 parts by mass of the silyl group-containing resin.

4. An easily dismantled adhesive sheet according to claim 3, wherein the weight-average molecular weight Mw of the acrylic tackifying resin is 300 or more and 10,000 or less.

5. An easily dismantled adhesive sheet according to claim 1 or claim 2, comprising a release liner provided on at least one surface of the adhesive layer.

6. An easily dismantled adhesive sheet according to claim 1 or claim 2, comprising: a base material; and the adhesive layer provided on at least one surface of the base material.

7. An easily dismantled adhesive sheet according to claim 1 or claim 2, wherein the adhesive force at 180° peel at 23°C obtained by performing the operations (S1-1) to (S1-3) below is defined as Ps0, and the operations (S2-1) to (S2-4) below are performed five times, with a different easily dismantled adhesive sheet from the one used to measure Ps0, and after the completion of the five cycles, the adhesive force retention rate (%) of Ps6 at 23°C obtained by performing the operations (S3-1) to (S3-3) below is defined as Ps6, and the adhesive force retention rate (%) of Ps6 relative to Ps0 satisfies the following formula (Equation 1). 120% ≥ (Ps6 / Ps0) × 100 ≥ 90% ... (Equation 1) (S1-1): The first test specimen is obtained by attaching the easily disassembled adhesive sheet for the first test specimen to the adherend for the first test specimen in a 23°C environment. (S1-2): The first test specimen is left standing for 30 minutes in a 23°C environment. (S1-3): After the standing in (S1-2), the 180° peel adhesion strength of the first test specimen at 23°C is measured in accordance with the measurement method specified in JIS Z0237:2022. (S2-1): A second test specimen is obtained by attaching a second easily disassembled adhesive sheet, different from the first test specimen adhesive sheet, to a second test specimen substrate, different from the first test specimen substrate, in a 23°C environment. (S2-2): The second test specimen is left standing in a 120°C environment for 30 minutes. (S2-3): After the standing in (S2-2), the 180° peel-off adhesive strength of the second test specimen at 120°C is measured in accordance with the measurement method specified in JIS Z0237:2022. (S2-4): The second test specimen substrate and the second easily disassembled adhesive sheet, peeled off in (S2-3), are left standing until they cool to 23°C.(S3-1): After cooling as described in (S2-4), the substrate for the second test specimen obtained by performing the operations from (S2-1) to (S2-4) five times is used as the substrate for the third test specimen, and the easily removable adhesive sheet for the second test specimen obtained by performing the operations from (S2-1) to (S2-4) five times is attached to the substrate for the third test specimen in a 23°C environment to obtain the third test specimen, (S3-2): The third test specimen is left to stand for 30 minutes in a 23°C environment, (S3-3): After standing as described in (S3-2), the 180° peel adhesion strength of the third test specimen at 23°C is measured in accordance with the measurement method specified in JIS Z0237:2022.

8. An easily dismantled adhesive sheet according to claim 7, wherein when the 180° peel-off adhesive force at 120°C obtained by performing the operations (S2-1) to (S2-3) in the first cycle is Ps1, the ratio of Ps1 to Ps0 satisfies the following formula (Equation 2): 0.2 ≥ (Ps1 / Ps0) > 0 ... (Equation 2) 9. A laminated structure comprising: a first adherend comprising at least one material selected from the group consisting of metal, glass, and resin; a second adherend composed of the same material as the first adherend or composed of different materials, comprising at least one material selected from the group consisting of metal, glass, and resin; and an easily disassembled adhesive sheet according to claim 1 or 2, provided between the first adherend and the second adherend and attached to the first adherend and the second adherend.

10. A dismantling method for dismantling a laminated structure, comprising: a step of preparing a laminated structure comprising: a first adherend comprising at least one material selected from the group consisting of metal, glass, and resin; a second adherend composed of the same material as the first adherend or of different materials, comprising at least one material selected from the group consisting of metal, glass, and resin; and an easily dismantled adhesive sheet according to claim 1 or 2, provided between the first adherend and the second adherend and attached to the first adherend and the second adherend; a step of heating the laminated structure; and a step of separating the first adherend and the second adherend and the easily dismantled adhesive sheet after heating the laminated structure until it cools to the ambient temperature of the dismantling work environment, wherein the easily dismantled adhesive sheet consists only of the adhesive layer.

11. A method for dismantling a laminated structure, comprising: a step of preparing a laminated structure comprising: a first adherend comprising at least one material selected from the group consisting of metal, glass, and resin; a second adherend composed of the same material as the first adherend or composed of different materials and comprising at least one material selected from the group consisting of metal, glass, and resin; and an easily dismantled adhesive sheet according to claim 1 or 2, provided between the first adherend and the second adherend and attached to the first adherend and the second adherend; a step of heating the laminated structure; and a step of, after heating the laminated structure and before it cools to the ambient temperature of the dismantling work environment, either the first adherend or the second adherend is not separated from the easily dismantled adhesive sheet, and the other of the first adherend or the second adherend that was not separated from the easily dismantled adhesive sheet is separated from the easily dismantled adhesive sheet, wherein the easily dismantled adhesive sheet consists only of the adhesive layer. Disassembly method.

12. A dismantling method for dismantling a laminated structure, comprising: a step of preparing a laminated structure comprising: a first adherend comprising at least one material selected from the group consisting of metal, glass, and resin; a second adherend composed of the same material as the first adherend or composed of different materials and comprising at least one material selected from the group consisting of metal, glass, and resin; and an easily dismantled adhesive sheet according to claim 1 or 2, provided between the first adherend and the second adherend and attached to the first adherend and the second adherend; a step of heating the laminated structure; and a step of separating the first adherend and the second adherend and the easily dismantled adhesive sheet after heating the laminated structure until it cools to the ambient temperature of the dismantling work environment, wherein the easily dismantled adhesive sheet comprises a base material and adhesive layers provided on both sides of the base material.

13. A method for dismantling a laminated structure, comprising: a step of preparing a laminated structure comprising: a first adherend comprising at least one material selected from the group consisting of metal, glass, and resin; a second adherend composed of the same material as the first adherend or composed of different materials and comprising at least one material selected from the group consisting of metal, glass, and resin; and an easily dismantled adhesive sheet according to claim 1 or 2, provided between the first adherend and the second adherend and attached to the first adherend and the second adherend; a step of heating the laminated structure; and a step of, after heating the laminated structure and before it cools to the ambient temperature of the dismantling work environment, either the first adherend or the second adherend is not separated from the easily dismantled adhesive sheet, and the other of the first adherend or the second adherend that was not separated from the easily dismantled adhesive sheet is separated from the easily dismantled adhesive sheet. A method for dismantling the easily dismantled adhesive sheet, comprising a base material and adhesive layers provided on both sides of the base material.

14. A method for using an easily dismantled adhesive sheet, comprising the steps of: attaching an easily dismantled adhesive sheet according to claim 1 or claim 2 to an adherend comprising at least one material selected from the group consisting of metal, glass, and resin; separating the adherend and the easily dismantled adhesive sheet; and, after the separation step, attaching the easily dismantled adhesive sheet to the adherend, or another adherend different from the adherend.

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