Adhesive sheets, and methods for manufacturing articles and articles.

Abstract

This invention provides an adhesive sheet, an article using the adhesive sheet, and a method for manufacturing the same. The adhesive sheet, which expands upon heating, balances temporary fixation at room temperature before expansion with ease of insertion when one component is inserted into a gap between two components. After expansion, it maintains excellent adhesive strength even at high temperatures, firmly bonding the components together. The invention provides an adhesive sheet having opposing first and second main surfaces. The first main surface of the adhesive sheet is composed of a thermosetting adhesive layer and a plurality of adhesive portions patterned on the first main surface of the thermosetting adhesive layer. The second main surface of the adhesive sheet is composed of the thermosetting adhesive layer or other thermosetting adhesive layers constituting the first main surface of the adhesive sheet.

Description

Technical Field

[0001] The present invention relates to adhesive sheets having an adhesive layer that can expand upon heating. Background Technology

[0002] The method of fixing a component into and securing it to a gap formed in another component or between two or more other components is used in the manufacturing of various products such as automobiles and electrical equipment. For example, in a motor installed in a hybrid vehicle, a magnet is inserted and secured into a gap located at a predetermined position in the core (rotor core). Furthermore, the component into which the gap is inserted is called the inserting component, and the component forming the gap, or the group of two or more components constituting the gap, is called the inserted component.

[0003] In the aforementioned fixing method, to prevent the inserted component from falling out of the gap, the inserting component is typically inserted into the gap of the inserted component, and then a liquid adhesive is used to fill the gap to join the inserting component and the inserted component. However, in this method, before the adhesive cures, the inserting component may sometimes shift position within the gap and fall out. Furthermore, the process is complex and sometimes time-consuming because adjustments to the viscosity and filling amount of the liquid adhesive are required. Moreover, in the aforementioned method, the adhesive adheres to the outside of the gap between the components, becoming a source of contamination.

[0004] Therefore, in recent years, methods for joining insert members and inserted members using adhesive sheets instead of liquid adhesives have been studied. Among these methods, a method is being studied in which an expandable adhesive sheet is disposed together with the insert member in the gap of the inserted member, and the adhesive sheet expands to fill the gap to join the insert member and the inserted member (e.g., Patent Documents 1 and 2). Existing technical documents Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2017-052950 Patent Document 2: Japanese Patent Application Publication No. 2019-182977 Summary of the Invention The technical problem that the invention aims to solve

[0006] In adhesive sheets used for joining insert components (i.e., adhered objects) and inserted components (i.e., adhered objects), the adhesive sheet needs to be inserted into the gap between the components before they can be joined together by heating and expansion. Therefore, to avoid hindering the insertion of the components, the initial adhesiveness of the adhesive sheet at room temperature before insertion is required to be low or non-existent. On the other hand, after insertion, the insert component and the inserted component cannot be immediately joined. Therefore, before the adhesive sheet is expanded, bonded, and fixed, it is required to have high initial adhesiveness at room temperature to prevent the adhesive sheet from shifting from the designated bonding position of the adhered objects. Furthermore, in the joining of components that are high-temperature components, such as automotive motors, high heat resistance is required. Therefore, the adhesive sheet is also required to exhibit excellent adhesive strength in high-temperature environments in addition to room temperature environments, so as to firmly join the insert component and the inserted component. However, conventional adhesive sheets used for joining insert components and inserted components have difficulty adequately balancing temporary fixation at room temperature, ease of insertion, and heat resistance.

[0007] The present invention was made in view of the above-mentioned actual situation. The present invention provides an adhesive sheet, an article using the adhesive sheet, and a method for manufacturing the same. In the adhesive sheet that can expand by heating, before expansion, it can take into account both temporary fixation at room temperature and ease of insertion when inserting one component into the gap of another component. After expansion, it can maintain excellent adhesive strength even in high temperature environment and firmly join the components together. Technical solutions for solving technical problems

[0008] First, the present invention provides an adhesive sheet having a first main surface and a second main surface opposite to each other. The first main surface of the adhesive sheet is composed of a thermosetting adhesive layer and a plurality of adhesive portions (the Japanese original for "adhesive portions" is "adhesive parts") patterned on the first main surface of the thermosetting adhesive layer. The second main surface of the adhesive sheet is composed of the thermosetting adhesive layer or other thermosetting adhesive layers constituting the first main surface of the adhesive sheet.

[0009] Second, the present invention provides an article having a first adhesive and a second adhesive, wherein the second adhesive has a gap, and the first adhesive is disposed in the gap of the second adhesive, wherein the first adhesive and the second adhesive are bonded together in the gap through an expansion of the adhesive sheet.

[0010] Furthermore, the present invention provides an article having a first adhesive, a third adhesive, and a fourth adhesive, with a gap between the third adhesive and the fourth adhesive, the first adhesive being disposed within the gap, and the first adhesive and the third adhesive, as well as the first adhesive and the fourth adhesive, being bonded together with an expansion of the adhesive sheet within the gap.

[0011] Third, the present invention provides a method for manufacturing an article, comprising the following steps: step [1A], wherein a first main surface of the adhesive sheet is adhered to the surface of a first adherend or to the surface of a gap formed in a second adherend; step [2A], wherein the first adherend is inserted into the gap; and step [3A], wherein the adhesive sheet is heated to expand and cure the thermosetting adhesive layer, and the first adherend and the second adherend are bonded together through the expanded material of the adhesive sheet.

[0012] Furthermore, the present invention provides a method for manufacturing an article comprising the following steps: step [1B], wherein a first main surface of the adhesive sheet is adhered to the surface of a first adherend or the surface of a gap formed by a third adherend and a fourth adherend; step [2B], wherein the first adherend is inserted into the gap; and step [3B], wherein the adhesive sheet is heated to expand and cure the thermosetting adhesive layer, and the first adherend, the third adherend, and the fourth adherend are bonded together through the expanded material of the adhesive sheet. Invention Effects

[0013] The adhesive sheet according to the present invention has thermal expansion properties, which can take into account both temporary fixation at room temperature before expansion and easy insertion of components into gaps. After expansion, it can maintain excellent adhesive strength even at high temperature to firmly join the components together. Attached Figure Description

[0014] Figure 1 This is a schematic cross-sectional view showing an example of the adhesive sheet of the present invention. Figure 2 This is a schematic cross-sectional view showing an example of the adhesive sheet of the present invention after expansion. Figure 3 This is a schematic cross-sectional view showing an example of the adhesive sheet of the present invention. Figure 4 This is a schematic cross-sectional view showing an example of the adhesive sheet of the present invention after expansion. Figure 5 This is a schematic cross-sectional view showing an example of the adhesive sheet of the present invention after expansion. Figure 6 This is a schematic cross-sectional view showing an example of the adhesive sheet of the present invention. Figure 7 This is a schematic cross-sectional view illustrating an example of a method for manufacturing the article of the present invention. Figure 8 This is a schematic cross-sectional view illustrating an example of a method for manufacturing the article of the present invention. Figure 9This is a schematic diagram illustrating the method for measuring the shear bond strength of an adhesive sheet after heating (expansion). Detailed Implementation

[0015] I. Adhesive sheet The adhesive sheet of the present invention is an adhesive sheet having a first main surface and a second main surface opposite to each other. The first main surface of the adhesive sheet is composed of a thermosetting adhesive layer and a plurality of adhesive portions patterned on the first main surface of the thermosetting adhesive layer. The second main surface of the adhesive sheet is composed of the thermosetting adhesive layer or other thermosetting adhesive layer constituting the first main surface of the adhesive sheet.

[0016] For example, in the expandable adhesive sheets disclosed in Patent Documents 1 and 2, the initial adhesion of the thermosetting expandable adhesive layer is low or nonexistent, making it difficult to easily and temporarily fix it to the adherend at room temperature. Furthermore, methods for temporary fixation to the adherend by heat lamination are also included, but because the material of the adherend is sometimes difficult to sufficiently fix temporarily by heat lamination, heat lamination equipment is sometimes required, making the process complicated. On the other hand, thermoplastic pressure-sensitive adhesive layers have poor heat resistance, so at high temperatures, the pressure-sensitive adhesive layer deteriorates, causing the adhesive force to decrease or disappear, making it difficult to firmly bond the insert member to the inserted member. Moreover, since the side opposite to the contact surface of the member with the pressure-sensitive adhesive layer also has initial adhesion, when inserting into a gap, the insert member may sometimes get stuck, or it may adhere outside the designated position, resulting in positional displacement. Therefore, in conventional expandable adhesive sheets, it is difficult to simultaneously achieve temporary fixation at room temperature, insertion capability, and heat resistance.

[0017] In contrast, the adhesive sheet according to the present invention can achieve both good temporary fixation and insertion at room temperature, and exhibits excellent heat resistance after expansion, maintaining excellent adhesive strength even at high temperatures. Specifically, the adhesive sheet of the present invention has a plurality of patterned adhesive portions on its first main surface, allowing for temporary fixation to the adherend at room temperature using the initial adhesive strength of these portions. On the other hand, the second main surface is composed of a thermosetting adhesive layer, thus utilizing the low initial adhesive strength of this layer to prevent other adherends from attaching to the second main surface, allowing for easy insertion of the insert member into the gap. Furthermore, the aforementioned thermosetting adhesive layer expands upon heating to fill the gap between the insert member and the inserted member, while simultaneously curing upon heating, exhibiting high adhesive strength. At this point, on the first main surface of the adhesive sheet, due to the expansion of the thermosetting adhesive layer, the adhesive portions are filled or buried, thus allowing the expanded thermosetting adhesive layer to contact and firmly bond with a component. Furthermore, on the second main surface of the adhesive sheet, the expanded thermosetting adhesive layer can contact and firmly bond with another component. Therefore, the expanded adhesive sheet of the present invention bonds the expanded thermosetting adhesive layer and the component to both sides of the sheet, exhibiting high adhesive strength even at high temperatures, and can firmly fix the components together.

[0018] The first main surface of the adhesive sheet of the present invention is composed of a thermosetting adhesive layer and a plurality of adhesive portions arranged in a pattern on the surface of the thermosetting adhesive layer. The first main surface of the adhesive sheet may be a surface with raised adhesive portions on the surface of the thermosetting adhesive layer, or it may be a flat surface in which the surface of the thermosetting adhesive layer and the surface of the adhesive portions are in the same plane.

[0019] In a preferred embodiment of the adhesive sheet of the present invention, the adhesive portion has a first surface and a second surface opposite to it. Before expansion, in the thickness direction of the adhesive sheet, the first surface of the adhesive portion is located outside the first main surface of the thermosetting adhesive layer on which the adhesive portion is provided, and the second surface of the adhesive portion is in contact with or located between the first main surface of the thermosetting adhesive layer on which the adhesive portion is provided and the second main surface opposite to it. With this type of adhesive sheet, after expansion, in the thickness direction of the adhesive sheet, the first surface of the adhesive portion is located at the same position as the first main surface of the expanded thermosetting adhesive layer on which the adhesive portion is provided, or located between the first main surface and the second main surface opposite to it, and the second surface of the adhesive portion is located between the first main surface and the second main surface opposite to it. Hereinafter, the above-described method is sometimes referred to as the first embodiment of the adhesive sheet.

[0020] Figure 1 and Figure 2 This is a schematic cross-sectional view illustrating an example of a first embodiment of the adhesive sheet of the present invention. Figure 1 Indicates before expansion, Figure 2 This indicates expansion. It should be noted that, on the surface of the adhesive sheet, the surface on the Z side (thickness direction Z-Z') is the first principal surface of the adhesive sheet, and the surface on the Z' side is the second surface. For example... Figure 1 As shown in (a) and (b), in the adhesive sheet 10 before expansion, in the thickness direction Z-Z' of the sheet, the first surface b1 of the adhesive portion 2 is located outside the first main surface a1 of the thermosetting adhesive layer 1 on which the adhesive portion 2 is provided (opposite to the first main surface a1 of the thermosetting adhesive layer 1 and the thermosetting adhesive layer). Furthermore, as... Figure 1 As shown in (a), the second surface b2 of the adhesive portion 2 contacts the first main surface a1 of the thermally expandable thermosetting adhesive layer 1 on which the adhesive portion 2 is provided, or, as... Figure 1 As shown in (b), it is located between the first main surface a1 and the second main surface a2 of the thermosetting adhesive layer 1, which has an adhesive portion 2. On the other hand, as Figure 2 As shown, in the expanded adhesive sheet 10', the areas between the adhesive portions 2, i.e., the areas on the first main surface of the adhesive sheet where no adhesive portion 2 is provided (non-adhesive portion areas), are filled by the expanded thermally expandable thermosetting adhesive layer 1'. Thus, as... Figure 2 As shown in (a), in the thickness direction Z-Z' of the sheet, the first surface b1 of the adhesive portion 2 is located at the same position as the first main surface a1 of the expanded thermally expandable thermosetting adhesive layer 1' provided with the adhesive portion 2, or, as... Figure 2As shown in (b), it is located between the first main surface a1 and the second main surface a2 on the opposite side. Furthermore, at this time, the second surface b2 of the adhesive part 2 is located between the first main surface a1 and the second main surface a2 on the opposite side of the expanded thermally expandable thermosetting adhesive layer 1' provided with the adhesive part 2.

[0021] like Figure 1 and Figure 2 As shown, in the first embodiment of the adhesive sheet of the present invention, the adhesive portion is disposed on the aforementioned first main surface of the thermosetting adhesive layer, or a portion of the adhesive portion is located within the thermosetting adhesive layer, and the remaining portion protrudes from the first main surface of the thermosetting adhesive layer. That is, the first surface of the adhesive sheet is a concave-convex surface where the adhesive portion is convex and the surface area of ​​the thermosetting adhesive layer where the adhesive portion is not provided (the non-adhesive portion area) is concave. Thus, before expansion, the adhesive portion of the adhesive sheet in the first main surface can contact one of the insert member and the inserted member to provide temporary fixation. Furthermore, the second main surface of the adhesive sheet is a surface composed of the thermosetting adhesive layer and does not have an adhesive portion, thus enabling the insertion of the insert member. On the other hand, after expansion, the expansion of the thermosetting adhesive layer fills the spaces between the adhesive portions on the first surface of the sheet, resulting in a shape where the adhesive portion is embedded in the thermosetting adhesive layer. In addition, the thermosetting adhesive layer exhibits high adhesive strength by expanding and curing through heating. Thus, the expanded thermosetting adhesive layer on the first and second main surfaces of the adhesive sheet can be firmly bonded to the insert member and the inserted member by contacting the expanded adhesive sheet. In the first embodiment of the adhesive sheet according to the present invention, when the adhesive sheet of the present invention is temporarily fixed to the insert member, i.e., the adherend, at room temperature, air bubbles trapped in the interface of the adherend are quickly removed, preventing air bubbles from remaining at the interface. This is preferable in that it can suppress poor adhesion of the adhesive sheet.

[0022] Furthermore, in one preferred embodiment of the adhesive sheet of the present invention, the adhesive portion has a first surface and a second surface opposite to it. Before expansion, in the thickness direction of the adhesive sheet, the first surface of the adhesive portion is located at the same position as the first main surface of the thermosetting adhesive layer having the adhesive portion, and the second surface of the adhesive portion is located between the first main surface of the thermosetting adhesive layer having the adhesive portion and the second main surface opposite to it. With this type of adhesive sheet, after expansion, in the thickness direction of the adhesive sheet, the first surface of the adhesive portion is located at the same position as the first main surface of the expanded thermosetting adhesive layer having the adhesive portion, or between the first main surface and the second main surface opposite to it, and the second surface of the adhesive portion is located between the first main surface of the expanded thermosetting adhesive layer having the adhesive portion and the second main surface opposite to it. Hereinafter, the above-described embodiment will sometimes be referred to as a second embodiment of the adhesive sheet.

[0023] Figure 3 and Figure 4 This is a schematic cross-sectional view illustrating an example of a second embodiment of the adhesive sheet of the present invention. Figure 3 Indicates before expansion, Figure 4 This indicates expansion. Furthermore, in the surface of the adhesive sheet, the surface on the Z side along the thickness direction Z-Z' is the first principal surface of the adhesive sheet, and the surface on the Z' side is the second surface. For example... Figure 3 As shown, before expansion, in the thickness direction Z-Z' of the sheet material, the first surface b1 of the adhesive portion 2 is located at the same position as the first main surface a1 of the thermosetting adhesive layer 1 on which the adhesive portion 2 is provided, and the second surface b2 of the adhesive portion 2 is located between the first main surface a1 of the thermosetting adhesive layer 1 on which the adhesive portion 2 is provided and the second main surface a2 on the opposite side. On the other hand, as... Figure 4 As shown, in the expanded adhesive sheet 10', in the thickness direction Z-Z' of the sheet, the first surface b1 of the adhesive portion 2 is located at the same position as the first main surface a1 of the expanded thermally expandable thermosetting adhesive layer 1', which has the adhesive portion 2. Figure 4 (a)) or located between the first principal surface a1 and the second principal surface a2 on its opposite side ( Figure 4 (b)), the second surface b2 of the adhesive portion 2 is located between the first main surface a1 of the expanded thermally expandable thermosetting adhesive layer 1' provided with the adhesive portion 2 and the second main surface a2 on its opposite side.

[0024] like Figure 3 and Figure 4 As exemplified, in a second embodiment of the adhesive sheet of the present invention, the adhesive portion is embedded in a thermosetting adhesive layer, and the first main surface of the adhesive sheet has a region of the first main surface of the thermosetting adhesive layer and a region of the first surface of the adhesive portion in the same plane. Thus, when the adhesive sheet before expansion is attached to a component on its first main surface, the adhesive portion contacts the component and provides temporary fixation. Furthermore, the second main surface of the adhesive sheet is composed of a thermosetting adhesive layer and does not have an adhesive portion, thus enabling insertion of a component. On the other hand, in the expanded adhesive sheet, the thermosetting adhesive layer expands and cures upon heating, exhibiting high adhesive strength. Therefore, in both the first and second main surfaces of the expanded adhesive sheet, the expanded thermosetting adhesive layer contacts another component and provides a strong bond. In the second embodiment of the adhesive sheet according to the present invention, before expansion, it can be ensured that the first main surface of the thermosetting adhesive layer is uniformly filled between the adhesive portions, so it is difficult to produce poor filling of the thermosetting adhesive layer between the adhesive portions after heating, and it can be more uniformly bonded to the inserted member, i.e., the object to be bonded, which is preferred in this respect.

[0025] In the thickness direction of the adhesive sheet, "the first surface of the adhesive portion being located at the same position as the first main surface of the thermosetting adhesive layer where the adhesive portion is provided" means that the adhesive portion is embedded in the thermosetting adhesive layer, and the first surface of the adhesive portion and the first main surface of the thermosetting adhesive layer are located in the same plane. When the first surface of the adhesive portion and the first main surface of the thermosetting adhesive layer are at the same position, the first main surface of the adhesive sheet has an area (adhesive portion area) with a plurality of patterned adhesive portions and an area (non-adhesive portion area) where the surface of the thermosetting adhesive layer is exposed. Furthermore, in the thickness direction, "the second surface of the adhesive portion being located between the first main surface of the thermosetting adhesive layer where the adhesive portion is provided and its opposite second main surface" means that it does not include the case where the second surface of the adhesive portion and the first or second main surface of the thermosetting adhesive layer are at the same position (in the same plane) in the thickness direction. Furthermore, in the thickness direction of the expanded adhesive sheet, the first surface of the adhesive portion located between the first main surface and the second main surface of the expanded thermally expandable thermosetting adhesive layer means, for example... Figure 4 As shown in (b), the first surface b1 of the adhesive portion 2 can be completely covered by the expanded thermally expandable thermosetting adhesive layer 1', as... Figure 5 As shown, a portion of the first surface b1 of the adhesive portion 2 can also be exposed from the first main surface a1 of the expanded thermally expandable thermosetting adhesive layer 1'.

[0026] In the adhesive sheet of the present invention, when at least the second surface of the adhesive portion is located between the first main surface and the second main surface of the aforementioned thermosetting adhesive layer, that is, when part or all of the adhesive portion is located within the thermosetting adhesive layer, part or all of the adhesive portion located within the thermosetting adhesive layer may or may not penetrate the thermosetting adhesive layer. The phrase "the adhesive portion penetrates the thermosetting adhesive layer" refers to the presence of an adhesive composition constituting the thermosetting adhesive layer within the adhesive portion before expansion, and to the presence of at least a cured thermosetting resin contained in the adhesive composition constituting the thermosetting adhesive layer within the adhesive portion after expansion.

[0027] The expanded adhesive sheet only needs to ensure a tight seal between the expanded thermosetting adhesive layer and the adherend bonded through the adhesive sheet on both the first and second main surfaces. The shape of the adhesive portion in the expanded adhesive sheet is not particularly limited. The shape of the adhesive portion in the expanded adhesive sheet may be the same as or different from the shape of the adhesive portion in the unexpanded adhesive sheet. It should be noted that in the expanded adhesive sheet, if the first and / or second surfaces of the adhesive portion cannot be determined, the adhesive portion is embedded within the expanded thermosetting adhesive layer, thus satisfying the relationship between the first and second surfaces of the adhesive portion of the expanded adhesive sheet and the first and second main surfaces of the thermosetting adhesive layer as described in the first and second embodiments above.

[0028] The adhesive sheet of the present invention provides temporary fixation on a first main surface and insertion capability on a second main surface, typically with a shear bond strength on the first main surface greater than that on the second main surface. Specifically, the difference between the shear bond strength of the first and second main surfaces of the adhesive sheet is preferably 0.01 MPa or more, more preferably 0.1 MPa or more, further preferably 0.4 MPa or more, and more preferably 0.5 MPa or more. This is because by ensuring the difference in shear bond strength between the first and second main surfaces of the adhesive sheet falls within the aforementioned range, both the first and second main surfaces can fully perform their functions, preventing damage to the function performed on one surface from the function performed on the other. A larger difference in shear bond strength between the first and second main surfaces is preferable, but there is no particular limitation; for example, it can be set to 2 MPa or less, or even 1 MPa or less.

[0029] The first main surface of the adhesive sheet of the present invention only needs to have a shear bond strength sufficient to provide temporary fixation, and typically has a higher shear bond strength than the second main surface. The shear bond strength of the first main surface of the adhesive sheet can be set such that the difference between the shear bond strength of the first and second main surfaces is within the aforementioned range; specifically, it is preferably 0.2 MPa or more, more preferably 0.3 MPa or more, and even more preferably 0.5 MPa or more. From the viewpoint of achieving higher temporary fixation in the first main surface of the adhesive sheet, it is more preferably 1.0 MPa or more. Furthermore, the higher the shear bond strength of the first main surface of the adhesive sheet, the better. There is no particular upper limit to the shear bond strength; for example, it can be set to 2 MPa or 1 MPa. The shear bond strength of the first side of the adhesive sheet is mainly due to the shear bond strength of the adhesive portion constituting the first main side and the thermal expansion thermosetting adhesive layer, but it can be appropriately adjusted according to the layer composition of the adhesive sheet.

[0030] On the other hand, the second main surface of the adhesive sheet only needs to have a shear bond strength sufficient for insertion, and typically has a lower shear bond strength than the first main surface. The shear bond strength of the second main surface of the adhesive sheet can be set to be within the range described above, where the difference between it and the shear bond strength of the first main surface is within this range. Specifically, it is preferably less than 0.5 MPa, more preferably 0.3 MPa or less, and even more preferably 0.2 MPa or less. From the viewpoint of preventing adverse situations such as the second main surface of the adhesive sheet of the present invention being adhered to a position different from the intended position, and improving the insertion performance when inserting the insertion member into the gap, it is more preferably 0.1 MPa or less. Furthermore, the lower the shear bond strength of the second main surface, the more the initial adhesion disappears, and the more the insertion performance when inserting the insertion member into the gap is improved. Therefore, the lower limit is preferably 0 MPa, but it can also be 0.01 MPa or more. The shear bond strength of the second main surface of the adhesive sheet is mainly due to the shear bond strength of the thermally expandable thermosetting adhesive layer that constitutes the second main surface, but it can be adjusted according to the layer composition of the adhesive sheet.

[0031] The shear bond strength of each side of the adhesive sheet can be determined according to the tensile shear test described in JIS Z 1541 by the following method. First, cut the adhesive sheet into 10mm × 10mm pieces. On the surface of one aluminum plate A (15mm wide × 70mm long × 0.5mm thick) of two smooth aluminum plates after degreasing treatment, fix one of the first and second sides of the cut adhesive sheet (the non-testing side) with a strong adhesive. Then, attach the other side of the adhesive sheet (the testing side) to the surface of another aluminum plate B. The adhesive sheet is then clamped between the two aluminum plates A and B and pressed for 10 seconds at 23°C and a load of 0.5MPa to obtain the adhesive sheet as the test piece. Next, after placing the test piece at 23°C for 5 minutes, clamp the ends of the two aluminum plates A and B respectively, and perform a tensile test in the 180-degree direction at a speed of 10mm / min using a Tensilon tensile testing machine. The value obtained at this time can be used as the shear bond strength of the aluminum B-side adhesive sheet (the surface to be measured). It should be noted that the non-testing surface of the adhesive sheet is firmly fixed to the aluminum plate A with a strong adhesive. Therefore, peeling will not occur on the non-testing surface of the adhesive sheet during the tensile test, and it can be used as the shear bond strength of the testing surface for measurement.

[0032] It should be noted that the first and second sides of the adhesive sheet refer to one and the other outermost surfaces of the adhesive sheet excluding the release liner. Unless otherwise specified, when referred to as "adhesive sheet" or "thermally expanding thermosetting adhesive layer," it refers to the "adhesive sheet" or "thermally expanding thermosetting adhesive layer" before expansion. Furthermore, "expansion of the adhesive sheet" and "expansion of the thermosetting adhesive layer" refer to "expanded adhesive sheet" and "expanded thermosetting adhesive layer," respectively. "After expansion" refers to the thermosetting adhesive layer after expansion and curing; unless otherwise specified, it refers to "after heating at 150°C for 60 minutes."

[0033] 1. Thermally expandable thermosetting adhesive layer The thermally expandable thermosetting adhesive layer in this invention is a layer that expands and cures by heating.

[0034] The adhesive sheet of the present invention may have one or more thermosetting adhesive layers with thermal expansion. Two or more thermosetting adhesive layers may be directly stacked or stacked with an intermediate layer described later. In the case where the adhesive sheet of the present invention has one thermosetting adhesive layer, the second main surface of the adhesive sheet is constituted by the thermosetting adhesive layer constituting the first main surface of the adhesive sheet. That is, a plurality of adhesive portions are patterned on the first main surface of a single layer of thermosetting adhesive layer, and the second main surface becomes the second main surface of the adhesive sheet.

[0035] On the other hand, when the adhesive sheet of the present invention has two or more thermosetting adhesive layers, the second main surface of the adhesive sheet is composed of a thermosetting adhesive layer that is different from the thermosetting adhesive layer constituting the first main surface of the adhesive sheet. That is, in the two or more thermosetting adhesive layers, a plurality of adhesive portions are provided on one of the outermost thermosetting adhesive layers in the thickness direction of the adhesive sheet, thereby constituting the first main surface of the adhesive sheet, and the second main surface of the adhesive sheet is constituted by the other outermost thermosetting adhesive layer. In the case where the adhesive sheet of the present invention has two or more thermosetting adhesive layers, the composition and thickness of each thermosetting adhesive layer may be the same or different.

[0036] At least the thermally expandable thermosetting adhesive layer constituting the second main surface of the adhesive sheet of the present invention, in order to prevent adverse situations such as the second main surface of the adhesive sheet being pasted at a position different from the specified position and to improve insertability, generally has a shear bond strength lower than that of the adhesive portion, wherein it is more preferably low or non-existent in initial adhesion (adhesion).

[0037] The shear bond strength of the thermosetting adhesive layer constituting the second main surface of the adhesive sheet of the present invention is preferably less than 0.5 MPa, more preferably 0.3 MPa or less, more preferably 0.2 MPa or less, and even more preferably 0.1 MPa or less. By setting the shear bond strength to the above-mentioned value, when the adhesive sheet of the present invention is inserted into the gap of the inserted member, it is possible to prevent adverse situations such as being adhered to a position different from the intended position, and to improve the insertability. Furthermore, the lower the shear bond strength of the thermosetting adhesive layer, the more the initial adhesion disappears, and the more the insertability is improved when the inserted member is inserted into the gap. Therefore, the lower limit value is preferably 0 MPa, but it can also be 0.05 MPa or more.

[0038] Furthermore, when the adhesive sheet of the present invention has two or more thermosetting adhesive layers, the thermosetting adhesive layer constituting the second main surface of the adhesive sheet only needs to have the aforementioned shear bond strength. The shear bond strength of other thermosetting adhesive layers can be within the aforementioned range or greater than the aforementioned range. When the shear bond strength of the thermosetting adhesive layer with the adhesive portion is higher than the shear bond strength of the thermosetting adhesive layer constituting the second main surface, the temporary fixation of the first main surface of the adhesive sheet can be improved. The preferred range of the shear bond strength of the thermosetting adhesive layer with the adhesive portion in the above-described case can be the same as the preferred range of the shear bond strength of the adhesive portion described later.

[0039] The shear bond strength of the thermosetting adhesive layer with thermal expansion can be adjusted in a timely manner, for example, by the combination of resin components, inorganic fillers, lubricants and other additives contained in the thermosetting adhesive composition described later.

[0040] The shear bond strength of the thermosetting adhesive layer can be determined according to the tensile shear test described in JIS Z 1541 by the following method. First, to achieve the same thickness as the thermosetting adhesive layer in the adhesive sheet, an adhesive of the same composition is molded into a sheet. The molded material is cut into 10mm × 10mm pieces. The resulting material is clamped between two degreased, smooth-surfaced aluminum plates (15mm wide × 70mm long × 0.5mm thick) and pressed together for 10 seconds at 23°C and a load of 0.5MPa. The resulting material is used as the test piece. After placing the test piece at 23°C for 5 minutes, the ends of the two aluminum plates are clamped, and a tensile test is performed in the 180-degree direction at 10mm / min using a Tensilon tensile testing machine. The value obtained at this time can be used as the shear bond strength.

[0041] To achieve even better adhesive strength, the thickness of the thermosetting adhesive layer is preferably 1 μm or more, more preferably in the range of 10 μm to 400 μm, even more preferably in the range of 15 μm to 250 μm, and particularly preferably in the range of 20 μm to 200 μm. When there are two or more thermosetting adhesive layers, the thickness is set to the thickness of each layer.

[0042] Furthermore, the thickness of the thermosetting adhesive layer is preferably 10% or more, more preferably 30% or more, relative to the total thickness of the adhesive sheet. By setting it to the above range, for example, it is easy to fix another object (inserted member) within a gap in one object (inserted member), or to fill the gap using the adhesive sheet. In the case of having two or more thermosetting adhesive layers, the total thickness of the thermosetting adhesive layer is preferably within the above range relative to the total thickness of the adhesive sheet.

[0043] The thermosetting adhesive layer is a layer that expands upon heating. After heating at 150°C for 60 minutes, the expansion rate in the thickness direction of the thermosetting adhesive layer is preferably 150% or more, more preferably 175% or more, and even more preferably 200% or more. Furthermore, the expansion rate is preferably 1000% or less, more preferably 800% or less, and even more preferably 500% or less. If the thermosetting adhesive layer is an adhesive sheet exhibiting the above expansion rate, even when the height (thickness) of the gap between the inserted components is large, the adhesive sheet can expand to properly fix another adhered object within the gap, or the adhesive sheet can fill the gap. Furthermore, even when the surface of the adhered object is rough or uneven, sufficient adhesion can be achieved, and the other adhered object can be properly fixed. Moreover, if the expansion rate is too high, the layer density decreases, and it is prone to deterioration due to high-temperature exposure. However, by keeping the expansion rate within the above range, thermal deterioration is difficult to occur, and high adhesive strength can be maintained even in high-temperature environments. It should be noted that when there are two or more thermosetting adhesive layers with thermal expansion, the expansion rate is set for each layer.

[0044] The thickness-direction expansion rate (%) of the thermosetting adhesive layer after heating at 150°C for 60 minutes was calculated based on the following method and mathematical formula. First, the thickness of the thermosetting adhesive layer A of the adhesive sheet before heating (before expansion) was measured at 23°C. Next, the adhesive sheet was left to stand at 150°C for 60 minutes and then heated. The adhesive sheet was then removed and placed at 23°C, and the thickness of the thermosetting adhesive layer of the adhesive sheet after heating (after expansion) was immediately measured. Based on the above measurement results and the following mathematical formula, the expansion rate was calculated. The thickness expansion rate (%) of the thermosetting adhesive layer after heating = [thickness of the thermosetting adhesive layer after heating / thickness of the thermosetting adhesive layer before heating] × 100 (%)

[0045] It should be noted that, instead of the adhesive sheet, a thermosetting adhesive layer with the same composition and thickness as the thermosetting adhesive layer of the adhesive sheet is formed on the release liner as the test sample. The thickness of the test sample before and after heating at 150°C for 60 minutes and the expansion rate can also be calculated based on the above mathematical formula.

[0046] The thickness of the expanded thermosetting adhesive layer, i.e., the expanded adhesive layer formed by expanding and curing the thermosetting adhesive layer through heating, is preferably in the range of 20 μm to 2500 μm, and more preferably in the range of 40 μm to 1500 μm, for obtaining even better adhesive strength. Furthermore, the expanded thermosetting adhesive layer preferably has a porous structure.

[0047] The glass transition temperature of the expanded thermosetting adhesive layer is preferably 80°C or higher. This is because the expanded adhesive layer maintains excellent adhesive strength even when exposed to high temperatures, particularly ensuring a firm bond between the insert and the inserted component in applications where high temperatures are easily reached. More specifically, the glass transition temperature of the expanded thermosetting adhesive layer is preferably 80°C or higher, more preferably 100°C or higher, further preferably 120°C or higher, and even more preferably 150°C or higher. It should be noted that the upper limit of the glass transition temperature of the expanded thermosetting adhesive layer is not particularly limited; for example, by setting it to 300°C or lower, bonding can be achieved without damaging the insert and the inserted component. When the adhesive sheet of the present invention has two or more thermally expandable thermosetting adhesive layers, it is preferable that at least the thermally expandable thermosetting adhesive layers constituting the first main surface and the second main surface of the adhesive sheet have a glass transition temperature within the range described above after expansion (curing), and preferably all the thermally expandable thermosetting adhesive layers have a glass transition temperature within the range described above after expansion (curing).

[0048] The glass transition temperature of the expanded thermosetting adhesive layer refers to the peak temperature identified in the spectrum of the loss tangent (tanδ) calculated from the value obtained by dividing the loss modulus (E”) by the storage modulus (E” / E’) at a frequency of 1 Hz using a dynamic viscoelasticity measuring apparatus (manufactured by Rheometrics, trade name: RSA-II). This is achieved by clamping the test piece with the measuring section of the testing machine, i.e., the fixture, and measuring the storage modulus (E’) and loss modulus (E”) at a frequency of 1 Hz. It should be noted that the test piece used in the above measurement can be a test piece obtained by heating the thermosetting adhesive layer at 150°C for 60 minutes and then punching the expanded thermosetting adhesive layer into the shape of test piece type 5 according to JIS K 7127 using a dumbbell-shaped cutter.

[0049] The aforementioned expanded thermosetting adhesive layer preferably has a curing rate of 80% or more. By setting this curing rate, excellent adhesive strength can be maintained even when exposed to high-temperature environments, especially for applications where the insertion member and the inserted member are easily subjected to high temperatures. Furthermore, as the aforementioned expanded (after heating) thermosetting adhesive layer, a curing rate of 90% or more is more preferable, and a curing rate of 99% or more is even more preferable.

[0050] It should be noted that the curing rate of the expanded thermosetting adhesive layer mentioned above refers to the mass of the dried thermosetting adhesive layer remaining in the solvent after heating the thermosetting adhesive layer at 150°C for 60 minutes and immersing the expanded thermosetting adhesive layer in a toluene solution adjusted to 23°C for 24 hours, expressed as gel fraction, and calculated based on the following mathematical formula.

[0051] Gel fraction (mass%) = {(mass of the thermosetting adhesive layer that does not dissolve in toluene and remains) / (mass of the thermosetting adhesive layer before toluene impregnation)} × 100

[0052] A thermosetting adhesive layer is a layer containing at least a thermosetting resin and an expanding agent. In other words, a thermosetting adhesive layer is a layer formed from a thermosetting adhesive composition containing at least a thermosetting resin and an expanding agent.

[0053] The aforementioned thermosetting adhesive layer can be formed, for example, by applying an adhesive composition containing a thermosetting resin and an expanding agent to a release liner and drying it. Furthermore, the expanded thermosetting adhesive layer is an expanded adhesive layer whose volume increases due to the expansion agent contained in the thermosetting adhesive composition expanding upon heating, and is formed from the cured product of the thermosetting adhesive composition.

[0054] It should be noted that the phrase "in all resin components of the thermally expandable thermosetting adhesive layer" can be defined as "in all resin components of the thermally expandable thermosetting adhesive composition that forms the thermally expandable thermosetting adhesive layer." Resin components refer to the resin components that constitute the adhesive composition excluding the expanding agent.

[0055] (Thermosetting resin) The thermosetting adhesive layer with thermal expansion properties contains at least a thermosetting resin as a resin component. As such a thermosetting resin, one or more thermosetting resins selected from polyurethane resins, phenolic resins, unsaturated polyester resins, epoxy resins, and acrylic resins can be used. Among these, epoxy resins and / or phenolic resins are preferred in terms of imparting good adhesion to the adhered objects upon thermal expansion; furthermore, epoxy resins are more preferred in terms of ensuring good heat curing properties and high heat resistance.

[0056] As the aforementioned epoxy resin, compounds having one or more epoxy groups in one molecule can be used. Specifically, bisphenol-type epoxy resins such as bisphenol A type epoxy resin and bisphenol F type epoxy resin and their modified resins, dicyclopentadiene-type epoxy resins such as dicyclopentadiene-phenol addition reaction type epoxy resins, biphenyl-type epoxy resins, tetramethylbiphenyl-type epoxy resins, polyhydroxynaphthalene-type epoxy resins, isocyanate-modified epoxy resins, 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide-modified epoxy resins, phenolic varnish-type epoxy resins, cresolic varnish-type epoxy resins, triphenylmethane-type epoxy resins, and tetraphenylethane-type epoxy resins can be used. Epoxy resins, including dicyclopentadiene-phenol addition reaction epoxy resins, phenol aralkyl type epoxy resins, naphthol phenolic varnish type epoxy resins, hexanediol type epoxy resins, naphthol aralkyl type epoxy resins, naphthol-phenol co-condensation phenolic varnish type epoxy resins, naphthol-cresol co-condensation phenolic varnish type epoxy resins, aromatic hydrocarbon formaldehyde resin modified phenolic resin type epoxy resins, biphenyl modified phenolic varnish type epoxy resins, trimethylolpropane type epoxy resins, alicyclic epoxy resins, acrylic resins with epoxy groups, polyurethane resins with epoxy groups, polyester resins with epoxy groups, and flexible epoxy resins, etc.

[0057] Epoxy resins can be used alone or in combination of two or more. Furthermore, epoxy resins can be solid, semi-solid, or liquid. Preferably, a multifunctional epoxy resin and / or a mixture thereof, having two or more epoxy groups per molecule, is used. Using such epoxy resins increases the glass transition temperature of the expanded thermosetting adhesive layer and suppresses the decrease in adhesive strength at high temperatures. Additionally, epoxy resins other than multifunctional epoxy resins can also be used in combination. By using these epoxy resins in combination, the flexibility, softening point, melt viscosity, and glass transition temperature of the thermosetting adhesive layer can be easily adjusted.

[0058] As the thermosetting resin included in the aforementioned thermosetting adhesive layer with thermal expansion, it is preferable to use a thermosetting resin with a total epoxy equivalent of 2000 g / eq. or less. This is preferred because it can increase the glass transition temperature of the expanded thermosetting adhesive layer and suppress the decrease in adhesive strength at high temperatures. The aforementioned total epoxy equivalent is preferably 50 g / eq. or more and 1500 g / eq. or less, 100 g / eq. or more and 1000 g / eq. or less, or 150 g / eq. or more and 500 g / eq. or less.

[0059] As the aforementioned thermosetting resin, the presence of epoxy resin with an epoxy equivalent of 500 g / eq. or less in the total resin composition of the thermosetting adhesive layer, ranging from 30% to 70% by mass, is preferred. This increases the glass transition temperature of the thermosetting adhesive layer after heat curing and suppresses the decrease in adhesive strength at high temperatures. The epoxy equivalent is preferably 50 g / eq. or more and 450 g / eq. or less, 100 g / eq. or more and 400 g / eq. or less, or 150 g / eq. or more and 300 g / eq. or less. Furthermore, the content of epoxy resin with an epoxy equivalent within the aforementioned range is preferably in the range of 35% by mass or more and 65% by mass or less, 40% by mass or more and 60% by mass or less, or 45% by mass or more and 55% by mass or less in the total resin composition of the thermosetting adhesive layer. The content of epoxy resin with epoxy equivalent within the above range is the total amount when there are two or more epoxy resins with epoxy equivalent within the above range.

[0060] It should be noted that "epoxy equivalent" is defined by the molecular weight of the epoxy resin for each epoxy group, and can be determined by the method described in JIS K7236, Method for Determining the Epoxy Equivalent of Epoxy Resins (2001) (perchloric acid-tetraethylammonium bromide method), etc.

[0061] The thermosetting adhesive layer with thermal expansion preferably comprises one or more solid thermosetting resins (hereinafter referred to as solid resins). "Solid resin" refers to a resin with a high softening point or a resin that is semi-solid or solid at 25°C. The softening point of the solid resin is preferably 5°C or higher. As a thermosetting resin, it is preferable to include a solid resin with a softening point of 30°C or higher and 150°C or lower, and more preferably a solid resin with a softening point of 50°C or higher and 100°C or lower.

[0062] The content of solid resin in the thermosetting adhesive layer can be appropriately set according to the required shear bond strength, etc., of the thermosetting adhesive layer. The content of the solid resin in the thermosetting adhesive layer constituting at least the second main surface of the adhesive sheet of the present invention is preferably 30% by mass or more, more preferably 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, 85% by mass or more, or 90% by mass or more, in the total resin composition of the thermosetting adhesive layer constituting the second main surface of the adhesive sheet. Furthermore, the above content is preferably 99% by mass or less, more preferably 97% by mass or 95% by mass, in the total resin composition of the thermosetting adhesive layer constituting the second main surface of the adhesive sheet. More specifically, the content of solid resin is preferably 30% by mass or more, more preferably 50% by mass or more and 99% by mass or less, and even more preferably 70% by mass or more and 95% by mass or less. The reason for this is that by including solid resin within the aforementioned range, the initial adhesion (bonding strength) of the thermosetting adhesive layer with thermal expansion can be reduced. When the insert member is inserted into the gap of the inserted member, it can prevent misalignment of the adhesive patch or adhesion to a position different from the specified position, and improve insertability. In cases containing two or more solid resins, the content of the solid resin is the total amount of the two or more solid resins.

[0063] Specifically, examples of the aforementioned solid resins include phenolic varnish-type epoxy resins, cresol varnish-type epoxy resins, triphenylmethane-type epoxy resins, tetraphenylethane-type epoxy resins, dicyclopentadiene-phenol addition reaction epoxy resins, phenol aralkyl-type epoxy resins, naphthol varnish-type epoxy resins, naphthol aralkyl-type epoxy resins, naphthol-phenol co-condensation phenolic varnish-type epoxy resins, and naphthol-cresol co-condensation phenolic varnish-type epoxy resins. These resins can be used alone or in combination with two or more other resins.

[0064] Furthermore, the thermosetting adhesive layer with thermal expansion can also be used, as needed, with a thermosetting resin that is liquid at room temperature (hereinafter, sometimes referred to as liquid resin). This is because the shear strength and other properties of the thermosetting adhesive layer can be adjusted to the desired values. As for the aforementioned liquid resin, its viscosity at 25°C is preferably 3 million mPa·sec or less, more preferably 1000 mPa·sec or more and 2 million mPa·sec or less, and even more preferably 10,000 mPa·sec or more and 1.5 million mPa·sec or less.

[0065] The content of liquid resin in the thermosetting adhesive layer can be appropriately set according to the required shear bond strength, etc., of the thermosetting adhesive layer. The content of the liquid resin in the thermosetting adhesive layer constituting at least the second main surface of the adhesive sheet of the present invention is preferably 40% by mass or less, more preferably 30% by mass or less, further preferably 20% by mass or less, and more preferably 10% by mass or less, in the total resin composition of the thermosetting adhesive layer. Furthermore, the content of the liquid resin can be 0% by mass, can exceed 0% by mass, can contain 1% by mass or more, can contain 3% by mass or more, and can contain 5% by mass or more. More specifically, the content can be set to 40% by mass or less, 1% by mass or more and 30% by mass or less, 3% by mass or more and 20% by mass or less, or 5% by mass or more and 10% by mass or less. By setting the content of the liquid resin in the thermosetting adhesive layer constituting the second main surface within the aforementioned range, initial adhesion (bonding strength) can be reduced. When the insert member is inserted into the gap of the inserted member, it is possible to prevent adverse situations such as misalignment of the adhesive sheet or adhesion to a position different from the specified position, and to improve insertability. Furthermore, by ensuring good flexibility before expansion and good flowability during heating of the thermosetting adhesive layer, the operability of the adhesive sheet of the present invention and the expansion rate of the adhesive sheet during heating are suitable. In cases containing two or more liquid resins, the content of the liquid resin is the total amount of the two or more liquid resins.

[0066] When the thermosetting adhesive layer constituting the second main surface of the adhesive sheet of the present invention contains a liquid resin, the liquid resin can be appropriately combined using the aforementioned viscosity range and content range. As an example of a preferred embodiment of the thermosetting adhesive layer constituting the second main surface of the adhesive sheet of the present invention, it is preferable to include 20% by mass or less of a liquid resin with a viscosity of 3 million mPa·sec or less, preferably 1% to 15% by mass of a liquid resin with a viscosity in the range of 1000 mPa·sec to 2 million mPa·sec, and preferably 3% to 10% by mass of a liquid resin with a viscosity in the range of 10,000 mPa·sec to 1,500,000 mPa·sec. This is because the shear bond strength of the second main surface of the adhesive sheet can be made sufficiently smaller than that of the first main surface, and the insertion properties are improved.

[0067] It should be noted that, regarding the thermo-expansion and thermo-curing adhesive layer other than the thermo-expansion and thermo-curing adhesive layer constituting the second main surface of the adhesive sheet, the content of liquid resin is not particularly limited and can be appropriately adjusted according to the required shear bond strength.

[0068] Specifically, examples of the aforementioned liquid resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin and other bisphenol-type epoxy resins and their modified resins, trimethylolpropane type epoxy resin, alicyclic epoxy resin, etc. A single liquid resin may be used, or two or more may be used.

[0069] When the thermosetting adhesive layer constituting the second main surface of the adhesive sheet of the present invention contains the aforementioned solid resin and liquid resin, the mixing ratio of solid resin to liquid resin (solid resin:liquid resin) is only required to achieve a shear bond strength within the desired range for the thermosetting adhesive layer. For example, a mass ratio preferably in the range of 99.9:0.1 to 60:40, preferably in the range of 99:1 to 70:30, and preferably in the range of 95:5 to 80:20. This is because by setting the mixing ratio of solid resin to liquid resin within the aforementioned range, the shear bond strength of the second main surface of the adhesive sheet can be made sufficiently lower than that of the first main surface.

[0070] The thermosetting resin is preferably contained in 10% by mass and 99% by mass or less of the total resin composition of the thermosetting adhesive layer, more preferably 20% by mass and 90% by mass or less, more preferably 30% by mass and 80% by mass or more, and even more preferably 40% by mass and 70% by mass or less. By ensuring that the content of the thermosetting resin in the thermosetting adhesive layer is within the above-mentioned range, the flexibility of the thermosetting adhesive layer before expansion and its flowability during heating are suitable, and the operability of the adhesive sheet of the present invention and the expansion rate of the adhesive sheet during heating are suitable.

[0071] (Curing agent) The thermosetting adhesive layer and the thermosetting adhesive composition constituting therefrom preferably contain a curing agent capable of reacting with the aforementioned thermosetting resin. This is because, when the thermosetting adhesive layer is heated, the thermosetting resin fully cures, exhibiting high adhesive strength. The curing agent is preferably contained before the thermosetting adhesive layer is heat-cured, or before it is formed into a sheet-like thermosetting adhesive layer.

[0072] The curing agent described above can be appropriately selected from compounds that correspond to the type of thermosetting resin, and particularly the type of functional groups possessed by the thermosetting resin. For example, when using epoxy resin as the thermosetting resin, a curing agent having functional groups capable of reacting with the epoxy group is preferred. Examples of curing agents include amine compounds, amide compounds, acid anhydride compounds, and phenolic compounds. A powder form of the curing agent is preferred.

[0073] For example, as amine compounds, diaminodiphenylmethane, diethylenetriamine, triethylenetetramine, diaminodiphenyl sulfone, isophorone diamine, imidazole derivatives, BF3-amino complexes, guanidine derivatives, etc., can be used.

[0074] Examples of the aforementioned amide compounds include dicyandiamide, dimers of linolenic acid, and polyamide resins synthesized from ethylenediamine.

[0075] Examples of the aforementioned anhydride compounds include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride.

[0076] Examples of the aforementioned phenolic compounds include phenol-formaldehyde varnish resin, cresol-formaldehyde varnish resin, aromatic hydrocarbon formaldehyde resin modified phenolic resin, dicyclopentadiene-phenol addition-type resin, phenol aralkyl resin (Xylok resin), naphthol aralkyl resin, trimethylolmethane resin, tetraphenol ethane resin, naphthol-formaldehyde varnish resin, naphthol-phenol co-condensation phenolic varnish resin, naphthol-cresol co-condensation phenolic varnish resin, biphenyl-modified phenolic resin (a polyphenolic compound obtained by linking a phenol core with a dimethylene group), biphenyl-modified naphthol resin (a polyphenolic compound obtained by linking a phenol core with a dimethylene group), aminotriazine-modified phenolic resin (a compound with a phenol skeleton, a triazine ring, and a primary amino group in its molecular structure), and alkoxy-containing aromatic ring-modified phenolic varnish resin (a polyphenolic compound obtained by linking an aromatic ring containing a phenol core and an alkoxy group with formaldehyde), among other polyphenolic compounds.

[0077] As the curing agent described above, for example, when epoxy resin is used as the thermosetting resin, the ratio of the equivalent of functional groups in the curing agent that can react with epoxy groups to the total epoxy equivalent of the thermosetting resin is preferably in the range of 0.3 or more and 2.0 or less, more preferably in the range of 0.5 or more and 1.5 or less, and even more preferably in the range of 0.7 or more and 1.0 or less. By using it within the above range, the thermosetting resin can be fully cured, and the heat resistance of the adhesive sheet can be improved.

[0078] The curing temperature of the aforementioned thermosetting material is preferably above the expansion temperature of the expanding agent described later, and the curing time is preferably above the expansion time. This allows the expanding agent to fully expand within the thermosetting material, which softens upon heating, resulting in a uniform sheet thickness after expansion.

[0079] (Curing accelerator) Furthermore, the thermosetting adhesive layer and the thermosetting adhesive composition constituting therefrom may also contain a curing accelerator. The curing accelerator is preferably contained before the thermosetting adhesive layer A is heat-cured, or before it is formed into a sheet-like thermosetting adhesive layer A.

[0080] Phosphorus compounds, amine compounds, imidazole derivatives, etc., can be used as the curing accelerators described above. The amount of the curing accelerator used is preferably 0.1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight, relative to 100 parts by weight of all resin components contained in the thermosetting adhesive layer.

[0081] As a curing accelerator, a powdered curing accelerator is preferred. Compared with a liquid curing accelerator, the powdered curing accelerator can suppress the thermosetting reaction at low temperatures, thus further improving the storage stability of thermosetting materials at room temperature before thermosetting.

[0082] (Thermoplastic resin) Furthermore, the thermoplastic adhesive layer and the thermoplastic adhesive composition constituting it can use materials containing thermoplastic resins without compromising the fixation of the joint, even when used in environments with large temperature variations after expansion and curing.

[0083] Examples of thermoplastic resins that can be used include thermoplastic polyurethane (TPU); phenoxy resins such as polyhydroxy polyethers synthesized from bisphenols and epichlorohydrin; polycarbonate (PC); vinyl chloride-based resins such as polyvinyl chloride (PVC) and vinyl chloride-vinyl acetate copolymer resins; acrylic resins such as polyacrylic acid, polymethacrylic acid, polymethyl acrylate, polymethyl methacrylate (PMMA), and polyethyl methacrylate; polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate, polypropylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate; polyamide resins such as nylon (registered trademark); and polystyrene (PS). Polystyrene resins such as imide-modified polystyrene, acrylonitrile-butadiene-styrene (ABS) resin, imide-modified ABS resin, styrene-acrylonitrile copolymer (SAN) resin, and acrylonitrile-ethylene-propylene-diene-styrene (AES) resin; olefin resins such as polyethylene (PE) resin, polypropylene (PP) resin, and cycloolefin resins; cellulose resins such as nitrocellulose and cellulose acetate; silicone resins; fluorinated resins; and thermoplastic elastomers such as styrene-based thermoplastic elastomers, olefin-based thermoplastic elastomers, vinyl chloride-based thermoplastic elastomers, urethane-based thermoplastic elastomers, ester-based thermoplastic elastomers, and amide-based thermoplastic elastomers.

[0084] The thermosetting adhesive layer preferably contains one or more thermoplastic resins (hereinafter sometimes referred to as reactive thermoplastic resins) having reactive groups that react with the thermosetting resin. This is because by allowing the reactive groups of the reactive thermoplastic resin to react with the thermosetting resin, the cured thermosetting adhesive layer exhibits stronger adhesion. Examples of reactive groups that react with the thermosetting resin include epoxy, hydroxyl, carboxyl, amino, and isocyanate groups. Furthermore, examples of thermoplastic resins having such reactive groups include thermoplastic polyurethane (TPU), polyhydroxy polyethers (phenoxy resins), and acrylic resins.

[0085] Based on the reasons described above, the aforementioned thermoplastic resin can be used in the range of 1 to 200 parts by weight relative to 100 parts by weight of the aforementioned thermosetting resin. Among these, it is preferable to use it in the range of 10 to 150 parts by weight relative to 100 parts by weight of the aforementioned thermosetting resin, and from the viewpoint of being able to exhibit strong adhesive strength, it is more preferable to use it in the range of 30 to 100 parts by weight.

[0086] (Expanding agent) As an expander included in the thermosetting adhesive layer and the thermosetting adhesive composition constituting thereof, it is preferable to use an expander that enables the thermosetting adhesive layer to form a porous structure within the layer after expansion. Examples of such expanders include inorganic compounds such as ammonium carbonate, ammonium bicarbonate, ammonium nitrite, ammonium borohydride, and azides; fluorinated alkanes such as trichlorofluoromethane; azo compounds such as azobisisobutyronitrile; hydrazine compounds such as p-toluenesulfonylhydrazine; aminourea compounds such as p-toluenesulfonylaminourea; triazole compounds such as 5-morpholino-1,2,3,4-thiatriazole; and N-nitroso compounds such as N,N'-dinitrosoterephthalamide.

[0087] Furthermore, as the aforementioned expanding agent, for example, expandable capsules obtained by microencapsulating hydrocarbon solvents can be used. Two or more of the aforementioned expanding agents can be used alone or in combination.

[0088] As the aforementioned expanding agent, the use of expanding capsules obtained by microencapsulating hydrocarbon solvents is preferred, for example, in preventing the deterioration of thermally expanding thermosetting adhesive layers caused by the effects of heat.

[0089] Furthermore, as the aforementioned expanding agent, it is preferable to use an expanding agent that can expand at temperatures before and after the softening point of the thermosetting adhesive layer, since it can fully expand the adhesive sheet.

[0090] Commercially available examples of the aforementioned expandable capsules include Expancel (manufactured by Japan Fillite Co., Ltd.), Matsumoto Microsphere (manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd.), and Microsphere (manufactured by KUREHA Co., Ltd.). When using such expandable capsules, it is preferable to use capsules whose expanded volume (volume expansion rate) is 8 to 60 times greater than the volume of the capsule before expansion.

[0091] The amount of the expanding agent used, preferably the amount of the thermally expandable capsule, is in the range of 0.3 to 30 parts by weight, more preferably 0.5 to 25 parts by weight, and even more preferably 1 to 20 parts by weight, relative to 100 parts by weight of the total resin component of the thermally expandable thermosetting adhesive layer. By using the expanding agent within the above-mentioned range, the gaps in the inserted member can be fully filled, and a better adhesive force can be obtained, enabling the insertion member or the inserted member to maintain a high adhesive force and firmly bond the insertion member and the inserted member together.

[0092] (Any ingredients) Furthermore, the thermosetting adhesive layer and the thermosetting adhesive composition constituting therefrom, in addition to the above-mentioned components, may, for example, use components containing fillers, softeners, stabilizers, adhesion promoters, leveling agents, defoamers, plasticizers, tackifying resins, fibers, antioxidants, ultraviolet absorbers, anti-hydrolysis agents, thickeners, pigments and other colorants, fillers and other additives, without impairing the effects of the present invention.

[0093] 2. Adhesive part In this invention, the adhesive portion is provided in a patterned manner on the first main surface of the thermally expandable thermosetting adhesive layer constituting the first main surface of the adhesive sheet, thereby constituting the first main surface of the adhesive sheet.

[0094] The first main surface of the adhesive sheet, having multiple adhesive portions, can at least demonstrate the desired shear bond strength by utilizing the initial adhesive force of the adhesive portions. After the insert member is inserted into the gap of the inserted member, during the period until the adhesive sheet is expanded to bond and fix the insert member and the inserted member, the adhesive sheet can be temporarily fixed to prevent it from shifting from the predetermined position.

[0095] The adhesive sheet of the present invention has a first main surface with a higher shear bond strength than the second main surface, thus exhibiting temporary fixation. Therefore, the shear bond strength of the plurality of adhesive portions is preferably 0.2 MPa or more, more preferably 0.3 MPa or more, further preferably 0.5 MPa or more, and more preferably 1.0 MPa or more. By setting it within the above range, an adhesive sheet with higher temporary fixation can be obtained. The higher the shear bond strength of the plurality of adhesive portions, the better, and there is no particular upper limit. For example, it can be set to 2 MPa or less, or even 1 MPa. The shear bond strength of the plurality of adhesive portions can be adjusted by adjusting the adhesive composition, the pattern, shape, size of each adhesive portion, and the proportion of the total area of ​​the plurality of adhesive portions in the first main surface of the adhesive sheet. It should be noted that the shear bond strength of the plurality of adhesive portions refers to, in other words, the shear bond strength of the adhesive layer composed of the plurality of adhesive portions and the non-adhesive portion areas where the aforementioned adhesive portions are not provided.

[0096] The shear bond strength of multiple adhesive parts can be determined according to the tensile shear test described in JIS Z 1541. Similar to the multiple adhesive parts of the adhesive sheet, multiple adhesive parts are patterned on the release liner. The adhesive parts are transferred to one of two smooth substrates (aluminum plates). Then, the substrates are overlapped with the adhesive parts in contact with the other substrate. The substrates are pressed together at 23°C for 10 seconds with a load of 0.5 MPa and left to stand at 23°C for 30 minutes. This is used as a test piece. The ends of the two aluminum plates of the test piece are clamped together, and a tensile test is performed in the 180-degree direction at 10 mm / min using a tensile testing machine to obtain the value.

[0097] The peak temperature of the loss tangent (tanδ) of the dynamic viscoelastic spectrum measured at the frequency of the adhesive portion (1 Hz) is not particularly limited, but is preferably -30°C to 20°C, more preferably -20°C to 10°C, and preferably -10°C to 5°C in order to maintain good adhesion.

[0098] The loss tangent based on dynamic viscoelastic spectra is measured using a viscoelastic testing machine (manufactured by Rheometrics, trade name: ARES 2KSTD). A test piece is clamped between parallel discs in the measuring section of the machine, and the storage modulus (G') and loss modulus (G”) at a frequency of 1 Hz are measured. The results are calculated using the mathematical formula tanδ = (G”) / (G'). Furthermore, the aforementioned peak temperature refers to the peak temperature confirmed using the spectrum of tanδ relative to the measurement temperature range (-50°C to 150°C). As the test piece, an adhesive layer with a thickness of 0.5 mm to 2.5 mm formed using the adhesive used in the formation of the adhesive portion can be used.

[0099] In this invention, the adhesive portions are provided in a patterned manner on the first main surface of the thermally expandable thermosetting adhesive layer, and there are non-adhesive portion regions between adjacent adhesive portions that do not contain the components constituting the adhesive portions.

[0100] Multiple adhesive parts are basically independent, but there may also be areas where two or more adhesive parts are partially connected. Examples of patterns for adhesive parts include dots (so-called islands), stripes (bands), and grids.

[0101] The top view shape of the adhesive portion (the shape viewed from the plane of the adhesive sheet) is preferably approximately circular, approximately quadrilateral, or approximately hexagonal. Approximately circular is not particularly limited, and the ratio of the maximum diameter to the minimum diameter of any adhesive portion [maximum diameter / minimum diameter] is preferably 1 to 4. The [maximum diameter / minimum diameter] is further preferably 1 to 2, and most preferably 1 to 1.5.

[0102] Furthermore, as a roughly quadrilateral shape, other possible shapes include roughly squares, roughly rectangles, roughly trapezoids, and roughly rhombuses. It should be noted that "roughly" in each shape indicates, for example, shapes where the corners of quadrilaterals and hexagons are rounded by pressing the adhesive portion, or shapes where straight sections become curved sections. The corners of the aforementioned roughly quadrilaterals are preferably roughly rhombuses with an angle of less than 90° towards the flow direction of the adhesive sheet, ranging from 45° to 70°, which maintains good adhesive strength and exhibits temporary fixation, and is therefore more preferable.

[0103] When the aforementioned adhesive portion is dot-shaped (so-called island-shaped), the size (area when viewed from above) of each adhesive portion is preferably 0.02 mm. 2 ~0.50mm 2 Within this range, 0.03mm is more preferred. 2 ~0.30mm 2 Within this range, 0.05 mm is particularly preferred. 2 ~0.20mm 2 Within the range described above, by setting the size of each adhesive part within the aforementioned range, the adhesive sheet maintains good temporary fixation before expansion, and after expansion, it does not hinder the filling between adhesive parts or the embedding of adhesive parts caused by the expansion of the thermosetting adhesive layer. The thermosetting adhesive layer that has expanded in the first main surface of the adhesive sheet can bond more firmly to the adhered object.

[0104] Furthermore, when the pattern of the adhesive portion is grid-like or striped, the top view shape of the adhesive portion can be, for example, a line. The line can be straight or wavy (serpentine, jagged). When the pattern of the adhesive portion is grid-like or striped, the width of the adhesive portion is not particularly limited as long as it achieves the aforementioned effect, and can be appropriately set according to the proportion of the total area of ​​the adhesive portions in the first main surface of the adhesive sheet, as described later.

[0105] The shapes and sizes of the aforementioned adhesive portions may be different or the same, but it is preferred that the shapes and sizes of each portion are substantially the same.

[0106] The shortest distance between any first adhesive portion selected from a plurality of adhesive portions and the second adhesive portion closest to the first adhesive portion (the closest existing one) is preferably in the range of 0.05 mm to 0.60 mm, more preferably in the range of 0.10 mm to 0.40 mm, and more preferably in the range of 0.15 mm to 0.30 mm. By ensuring that the shortest distance between two adjacent adhesive portions is within the above-mentioned range, the adhesive sheet maintains good temporary fixation before expansion, and after expansion, it does not hinder the filling between adhesive portions or the embedding of adhesive portions caused by the expansion of the thermosetting adhesive layer. The thermosetting adhesive layer, after expansion in the first main surface of the sheet, can bond more firmly to the adhered object. It should be noted that the distance between the first adhesive portion and the second adhesive portion adjacent to the first adhesive portion refers to the shortest distance between the first adhesive portion and the second adhesive portion adjacent to the first adhesive portion. Furthermore, when the pattern of the adhesive portion is grid-like or striped, the shortest distance between any first adhesive portion and the second adhesive portion closest to the first adhesive portion (the closest existing one) refers to the distance between the first adhesive portion and the second adhesive portion extending in the same direction as the first adhesive portion and approaching the first adhesive portion.

[0107] When viewed from above, the total area of ​​the aforementioned plurality of adhesive portions occupies 20% to 80% of the first main surface of the adhesive sheet of the present invention before expansion, more preferably 30% to 70%, and even more preferably 40% to 60%. By setting the proportion of the area of ​​the adhesive portions in the first main surface of the adhesive sheet within the aforementioned range, the first main surface of the adhesive sheet maintains good temporary fixation before expansion, and after expansion, it does not hinder the filling between adhesive portions or the embedding of adhesive portions caused by the expansion of the thermosetting adhesive layer. The thermosetting adhesive layer, after expansion in the first main surface of the sheet, can bond more firmly to the adhered object. It should be noted that the proportion of the total area of ​​the aforementioned plurality of adhesive portions is also referred to as the area occupancy rate of the adhesive portions in the first main surface of the adhesive sheet.

[0108] When viewed from above, the proportion of the total area of ​​the multiple adhesive portions in the first main surface of the adhesive sheet of the present invention before expansion is a value calculated by the following mathematical formula. The proportion of the total area of ​​multiple adhesive portions in the first main surface of the adhesive sheet before expansion = [the total area of ​​the adhesive portions when viewed from above in the adhesive sheet before expansion] / [the total area of ​​the first main surface of the adhesive sheet before expansion] × 100 (%)

[0109] The shape and size of the adhesive portion, the shortest distance between any first adhesive portion selected from multiple adhesive portions and the second adhesive portion closest to the first adhesive portion (the closest existing one), etc., can be determined, for example, by planar observation using an electron microscope.

[0110] The thickness of the adhesive portion is preferably 1 μm or more and 50 μm or less, more preferably 2 μm or more and 30 μm or less, and more preferably 3 μm or more and 10 μm or less. By setting the thickness within the above range, good temporary fixation can be obtained even when the surface of the adhered object is rough or uneven. Furthermore, even after heating the adhesive sheet of the present invention to expand the thermally expandable thermosetting adhesive layer to fill the gaps and fix it, excellent adhesive force can be obtained, which is therefore preferred.

[0111] The adhesive portion may or may not have thermal expansion properties, and can be appropriately set according to the composition of the adhesive constituting the adhesive portion. From the viewpoint that the adhesive sheet, after expansion, does not obstruct the filling or embedding of the adhesive portion between the adhesive portions caused by the expansion of the thermally expandable thermosetting adhesive layer, and that the expanded thermally expandable thermosetting adhesive layer can be more firmly bonded to the substrate in the first main surface of the adhesive portion, it is preferable that the adhesive portion does not have thermal expansion properties. The thickness expansion rate of the adhesive portion after heating at 150°C for 60 minutes is preferably 120% or less, preferably 115% or less, and most preferably 100% (the adhesive portion does not expand substantially).

[0112] The thickness expansion rate (%) of the adhesive portion refers to the ratio of the thickness of the adhesive portion after heating to the thickness of the adhesive portion before heating when the adhesive sheet of the present invention is heated at 150°C for 60 minutes. Specifically, it is a value calculated by the following method: First, the thickness of the adhesive portion of the adhesive sheet before heating (before expansion) is measured at 23°C. Next, after heating the adhesive sheet by standing it at 150°C for 60 minutes, the adhesive sheet is taken out and placed at 23°C, and the thickness of the adhesive portion of the adhesive sheet after heating (after expansion) is immediately measured. Based on the above measurement results and the following mathematical formula, the expansion rate is calculated. Expansion rate (%) of the adhesive portion in the thickness direction = [thickness of the adhesive portion after heating / thickness of the adhesive portion before heating] × 100

[0113] The gel fraction of the adhesive portion is preferably 60% by mass or less, more preferably 10% to 55% by mass, and even more preferably 20% to 50% by mass. This is because by making the gel fraction of the adhesive portion within the above-mentioned range, the surface shape of the adhesive portion is easily maintained, thus easily preventing shape changes over time, and enabling it to have sufficient initial adhesion in the first main surface of the adhesive sheet to provide temporary fixation.

[0114] The gel fraction of the adhesive portion is the same as that of the adhesive sheet of the present invention and can be calculated based on the proportion of insoluble components when a patterned adhesive portion is formed on the release liner and immersed in toluene for 24 hours, by the following mathematical formula. Gel fraction (mass%) = {(mass of the adhesive portion after toluene impregnation) / (mass of the adhesive portion before toluene impregnation)} × 100

[0115] The adhesive composition constituting the adhesive portion preferably uses a composition that exhibits excellent initial adhesive strength (adhesive force) at room temperature (23°C) and also demonstrates excellent adhesive strength even after the adhesive sheet of the present invention has been heated and expanded. Examples of such adhesive compositions include compositions comprising at least an adhesive resin.

[0116] The adhesive resin contained in the adhesive composition can be, for example, acrylic resin, rubber resin, polyurethane resin, polyester resin, silicone resin, etc. Among these, an acrylic resin is preferably included as the main component of the adhesive composition. The main component refers to the component present in the largest quantity in the adhesive composition.

[0117] As the aforementioned acrylic resin, for example, a substance obtained by polymerizing a monomer containing an alkyl methacrylate can be used, such as a combination of one or more of methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, n-octyl methacrylate, isooctyl methacrylate, isononyl methacrylate, cyclohexyl methacrylate, and 2-methylhexyl methacrylate. Among these, alkyl methacrylates are more preferably used from the perspective of obtaining an adhesive sheet with excellent conformability and adhesion to the surface of the adherend, as well as excellent adhesion and handling.

[0118] In addition to the substances mentioned above, acrylonitrile, (meth)acrylic acid, maleic anhydride, acrylamide, itaconic acid, styrene, vinyl acetate, etc., can also be used as monomers.

[0119] Examples of styrene-based rubber resins include, for instance, styrene-based AB-type diblock copolymers such as styrene-ethylene-butene copolymer (SEB); styrene-based ABA-type triblock copolymers such as styrene-butadiene-styrene copolymer (SBS), hydrogenated SBS (styrene-ethylene-butene-styrene copolymer (SEBS)), styrene-isoprene-styrene copolymer (SIS), hydrogenated SIS (styrene-ethylene-propylene-styrene copolymer (SEPS)), styrene-isobutylene-styrene copolymer (SIBS); styrene-based ABAB-type tetrablock copolymers such as styrene-butadiene-styrene-butadiene (SBSB); styrene-based ABABA-type pentablock copolymers such as styrene-butadiene-styrene-butadiene-styrene (SBSBS); styrene-based multiblock copolymers having more than one of these AB repeating units; and hydrogenated products obtained by hydrogenating the olefinic double bonds of styrene-based random copolymers such as styrene-butadiene rubber (SBR); etc. Commercially available styrene-based thermoplastic elastomers may also be used.

[0120] In addition to the resins described above, the adhesive composition may also contain tackifying resins, crosslinking agents, and other additives as needed.

[0121] As the aforementioned tackifying resin, for the purpose of adjusting the strong adhesion of the adhesive part, for example, rosin-based tackifying resin, polymerized rosin-based tackifying resin, polymerized rosin ester-based tackifying resin, rosin phenol-based tackifying resin, stabilized rosin ester-based tackifying resin, disproportionated rosin ester-based tackifying resin, terpene-based tackifying resin, terpene phenol-based tackifying resin, petroleum resin-based tackifying resin, etc., can be used.

[0122] As the aforementioned crosslinking agent, for the purpose of improving the cohesive force of the adhesive portion, known isocyanate-based crosslinking agents, epoxy-based crosslinking agents, aziridine-based crosslinking agents, polyvalent metal salt-based crosslinking agents, metal chelate-based crosslinking agents, ketone-hydrazide-based crosslinking agents, oxazoline-based crosslinking agents, carbodiimide-based crosslinking agents, silane-based crosslinking agents, glycidyl (alkoxy)epoxysilane-based crosslinking agents, etc., can be used.

[0123] As the above-mentioned additives, known materials such as alkalis (ammonia, etc.), acids, foaming agents, plasticizers, softeners, antioxidants, glass or plastic fibrous, spherical, beaded, or metal powder fillers, pigments, dyes, etc., pH adjusters, film-forming aids, leveling agents, thickeners, waterproofing agents, defoamers, and expanding agents can be used as needed, without hindering the desired effects of the present invention.

[0124] Examples of adhesive compositions include solvent-based adhesives, emulsion adhesives, water-based adhesives such as water-soluble adhesives, hot-melt adhesives, UV-curable adhesives, and EB-curable adhesives such as solvent-free adhesives.

[0125] The adhesive composition can utilize components containing solvents to maintain good coating operability. Examples of such solvents include toluene, xylene, ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, and hexane. Furthermore, in the case of using a water-based adhesive composition, water or a water-based solvent can be used as the solvent. It should be noted that the "total amount of the adhesive composition" when specifying the content of each component does not include the amount of solvent.

[0126] 3. Arbitrary composition The adhesive sheet of the present invention has at least an adhesive portion and a thermally expanding thermosetting adhesive layer, but may have any configuration as needed. For example... Figure 6 As illustrated, the adhesive sheet of the present invention may also include: a first thermosetting adhesive layer 1A having a first main surface a11 and a second main surface a21; a second thermosetting adhesive layer 1B having a first main surface a21 and a second main surface a22; and an intermediate layer 3 disposed between the first thermosetting adhesive layer 1A and the second thermosetting adhesive layer 1B, and bonded to the second main surface a21 of the first thermosetting adhesive layer 1A and the first main surface a12 of the second thermosetting adhesive layer 1B. A plurality of adhesive portions 2 arranged in a pattern may be provided on the first main surface a11 of the first thermosetting adhesive layer 1A. Figure 6 The adhesive sheet of the present invention, which has an intermediate layer 3, has good rigidity and superior bonding performance because its first main surface is composed of an adhesive portion 2 and a first thermally expandable thermosetting adhesive layer 1A, and its second main surface is composed of a second thermally expandable thermosetting adhesive layer 1B.

[0127] The intermediate layer is preferably a heat-resistant substrate. The level of heat resistance of the substrate varies depending on the application, and the melting point of the substrate is preferably 150°C or higher, more preferably 200°C or higher, and even more preferably 250°C or higher.

[0128] It should be noted that the melting point mentioned above refers to the temperature representing the maximum endothermic peak, which is determined by using a differential scanning calorimeter (DSC) to heat the intermediate layer (substrate) from 30°C at a heating rate of 10°C / minute.

[0129] Specifically, examples of substrates possessing the aforementioned heat resistance include polybutylene terephthalate, polyethylene naphthalate (PEN), polyamide, polyimide, polyetherimide, polysulfone, polyetheretherketone (PEEK), polyphenylene sulfide (PPS), and modified polyphenylene ether.

[0130] The intermediate layer preferably has a thickness of 1 μm or more and 200 μm or less, more preferably a thickness of 5 μm or more and 150 μm or less, and even more preferably a thickness of 10 μm or more and 100 μm or less. This is because, by setting the thickness of the intermediate layer within the aforementioned range, when the adhesive side of the adhesive sheet of the present invention is adhered to the substrate, even if the surface of the substrate is rough or uneven, it can adequately follow the surface shape of the substrate, resulting in excellent adhesion. The intermediate layer can be composed of a single layer of a substrate having the aforementioned heat resistance, or it can be composed of two or more layers of substrates having the same or different heat resistance properties.

[0131] The adhesive sheet of the present invention may have release liner layers provided on a first main surface having an adhesive portion and a second main surface opposite to the side having the adhesive portion. The release liner layers can be made of known materials such as resin films.

[0132] 4. Other The total thickness of the adhesive sheet before expansion (before heating) is preferably 10 μm or more and 600 μm or less, more preferably 50 μm or more and 500 μm or less, and more preferably 100 μm or more and 400 μm or less. Furthermore, the total thickness after expansion (after heating) is preferably 20 μm or more and 2500 μm or less, more preferably 40 μm or more and 2000 μm or less, and more preferably 100 μm or more and 1000 μm or less. It should be noted that the total thickness of the adhesive sheet does not include the thickness of the release liner.

[0133] The expanded shear bond strength of the adhesive sheet of the present invention is preferably 3 MPa or more at room temperature (23°C), more preferably 5 MPa or more, further preferably 6 MPa or more, and more preferably 9 MPa or more. This is because it exhibits excellent adhesion retention performance to the insert member and the inserted member. Furthermore, the expanded shear bond strength at 150°C is preferably 1 MPa or more, more preferably 4 MPa or more, and more preferably 7 MPa or more. This is because the adhesive sheet of the present invention exhibits the desired shear bond strength at the aforementioned temperature conditions, thus ensuring excellent adhesion retention performance to the insert member and the inserted member even at both room temperature and high temperature conditions, thereby achieving higher retention performance. The shear bond strength of the adhesive sheet of the present invention after expansion was measured by the method described in the embodiments below.

[0134] The adhesive sheet of the present invention can be manufactured, for example, by means of the following steps: applying a thermosetting adhesive composition to a release film and drying it to form a thermosetting adhesive layer; printing an adhesive composition in a desired pattern onto another release liner using a gravure coating machine or the like and drying it to form a plurality of patterned adhesive portions; and transferring and pressing the plurality of patterned adhesive portions onto the first main surface of the thermosetting adhesive layer. According to the above-described method for manufacturing adhesive sheets, in the process of transferring and pressing multiple patterned adhesive portions onto the first main surface of the above-described thermosetting adhesive layer, by adjusting the pressing load and temperature in a timely manner, it is also possible to manufacture adhesive portions formed on the first main surface of the thermosetting adhesive layer. Figure 1 (a) shows the manner in which a portion of the adhesive portion protrudes from the surface of the thermosetting adhesive layer. Figure 1 (b) shows the method), and the method of embedding a thermally expanding thermosetting adhesive layer in the adhesive portion ( Figure 3 Adhesive sheets in any of the ways shown.

[0135] If the adhesive sheet of the present invention is Figure 6 The intermediate layer illustrated herein can be manufactured, for example, by the following steps: applying a thermosetting adhesive composition to a release film and drying it to form a first thermosetting adhesive layer; applying a thermosetting adhesive composition to other release linings and drying it to form a second thermosetting adhesive layer; bonding an intermediate layer to the first thermosetting adhesive layer; bonding the second thermosetting adhesive layer to the side of the intermediate layer opposite to the first thermosetting adhesive layer; printing an adhesive composition in a desired pattern onto other release linings using a gravure coating machine and drying it to form a plurality of patterned adhesive portions; and transferring and pressing the patterned adhesive portions onto the first main surface of the first thermosetting adhesive layer.

[0136] The adhesive sheet of the present invention preferably expands in the thickness direction by heating, and preferably does not expand substantially in the surface direction (flow direction or width direction).

[0137] It should be noted that the adhesive sheet of the present invention is not limited to the application of bonding an insert member and an inserted member, and can be used for applications such as joining only two members or filling gaps in the adhered objects. For example, it can also be used in configurations where the adhesive sheet of the present invention is placed in a gap in the adhered object and then expanded to form a structure in which two or more portions in the gap are bonded by the adhesive sheet.

[0138] II. Items One aspect of the article of the present invention has a first adhesive and a second adhesive, wherein the second adhesive has a gap, and the first adhesive is disposed within the gap of the second adhesive, wherein the first adhesive and the second adhesive are bonded together through an expansion of the adhesive sheet described in the section "I. Adhesive Sheet".

[0139] According to this method, the gap between the first and second adhered objects is filled with an expanded portion of the adhesive sheet described in section "I. Adhesive Sheet," and the first and second adhered objects are bonded together through the expanded portion of the adhesive sheet. At this time, the thermosetting adhesive layer in the expanded portion of the adhesive sheet exhibits adhesive force by curing upon heating, and further expands, thereby enabling the expanded thermosetting adhesive layer to bond to the adhered objects not only on the second main surface of the adhesive sheet but also on the first main surface, maintaining high adhesive strength even at high temperatures. Therefore, it is possible to manufacture an article that can fix the first adhered object with high positional accuracy within the gap of the second adhered object while maintaining a strong bond between the first and second adhered objects even at high temperatures.

[0140] In the article of this method, one of the first and second adherends is bonded to the first main surface of the expanded adhesive sheet, and the other is bonded to the second main surface of the expanded adhesive sheet. From the viewpoint of ease of manufacture, which allows the article to be easily manufactured regardless of the width or size of the gap by inserting the adhesive sheet into the gap while it is attached to the first adherend, it is preferable that the first adherend is bonded to the first main surface of the expanded adhesive sheet, and the second adherend is bonded to the second main surface of the expanded adhesive sheet.

[0141] Furthermore, other embodiments of the article of the present invention include a first adhesive, a third adhesive, and a fourth adhesive, with a gap between the third adhesive and the fourth adhesive, the first adhesive being disposed within the gap, and the first adhesive and the third adhesive, as well as the first adhesive and the fourth adhesive, being bonded together with an expansion of the adhesive sheet described in the above-mentioned "I. Adhesive Sheet" section.

[0142] According to this method, in the gap between the third and fourth adhered objects, the expansion of the adhesive sheet described in section "I. Adhesive Sheet" is filled between the first and third adhered objects and between the first and fourth adhered objects, respectively. The first and third adhered objects, and the first and fourth adhered objects, are bonded together through the expansion of the adhesive sheet. At this time, the thermosetting adhesive layer in the expansion of the adhesive sheet exhibits adhesive force by curing upon heating, and further expands. Thus, the expanded thermosetting adhesive layer can bond to the adhered objects not only on the second main surface of the adhesive sheet but also on the first main surface, maintaining high adhesive strength even at high temperatures. Therefore, in the gap between the third and fourth adhered objects, the first adhered object is fixed with high positional accuracy, and an article capable of maintaining a firm bond between the first, third, and fourth adhered objects can be manufactured even at high temperatures.

[0143] In this type of article, the first, third, and fourth adhered objects are bonded to the first main surface of the expanded adhesive sheet, and preferably the third and fourth adhered objects are bonded to the second main surface of the expanded adhesive sheet, respectively. From the viewpoint of ease of manufacture, by inserting the adhesive sheet into a gap while it is attached to the first adhered object, the article can be easily manufactured regardless of the width or size of the gap. Therefore, it is preferable that the first adhered object is bonded to the first main surface of the expanded adhesive sheet, and the third and fourth adhered objects are bonded to the second main surface of the expanded adhesive sheet, respectively.

[0144] The "expansion of the adhesive sheet" in the article of the present invention is the substance resulting from the thermal expansion of the adhesive sheet described in the above-mentioned "I. Adhesive Sheet" section. Details have been provided in the above-mentioned section, and therefore, the description is omitted here. Furthermore, there are no particular limitations on the first to fourth adhered objects, and they can be appropriately selected depending on the type of article.

[0145] As an article of the present invention, the types of objects to be adhered can be appropriately selected, and therefore there is no particular limitation. For example, motors used in automobiles, civilian equipment, robots, etc. can be cited. When the article of the present invention is a motor, examples include combinations of using a magnet as the first adhered object and using a slotted rotor as the second adhered object, using insulating paper for insulating a slotted stator and wires disposed in the slot as the first adhered object, and using the slotted stator as the second adhered object, etc.

[0146] The articles of the present invention can be manufactured, for example, by the article manufacturing method described later.

[0147] III. Methods of manufacturing items The method of manufacturing the article of the present invention is a method of bonding two components together with an expansion of the adhesive sheet described in the above-mentioned item "I. Adhesive sheet", and in particular, a method of bonding an insertable component having a gap and an insertable component disposed in the gap together with an expansion of the adhesive sheet described in the above-mentioned item "I. Adhesive sheet".

[0148] As one method of manufacturing the article of the present invention, the method comprises the following steps: step [1A], wherein a first main surface of the adhesive sheet described in item "I. Adhesive sheet" is attached to the surface of the first adherend or to the surface of the gap formed in the second adherend; step [2A], wherein the first adherend is inserted into the gap; and step [3A], wherein the adhesive sheet is heated to expand and cure the thermosetting adhesive layer, and the first adherend and the second adherend are bonded together through the expanded material of the adhesive sheet.

[0149] Figure 7 This is a process diagram illustrating an example of a method for manufacturing the article of the present invention. First, the first main surface (the surface having the adhesive portion 2) of the adhesive sheet 10 described in section "I. Adhesive Sheet" is adhered to both sides of the first adherend 51. Figure 7 (a), process [1A]). Next, the first adhesive 51 to which the adhesive piece 10 is attached is inserted into the gap S formed in the second adhesive 52. Figure 7 (b), process [2A]). Next, the adhesive sheet 10 is heated to form a thermally expandable thermosetting adhesive layer ( Figure 7 (c) Symbol 1) expands and cures, bonding the expanded adhesive sheet 10' to the second substrate 52 via its second main surface (the side opposite to the surface with the adhesive portion 2). Figure 7 (c), process [3A]). At this time, the above-mentioned thermally expandable thermosetting adhesive layer (after expansion) is used. Figure 7 (c) The symbol 1') fills the gap S, and the expanded thermosetting adhesive layer is bonded to the side opposite to the side of the first adherend 51 and the second adherend 52. Thus, an article 50 is obtained by bonding the first adherend 51 and the second adherend 52 together with the expanded adhesive sheet 10'.

[0150] As another method of manufacturing the article of the present invention, it includes the following steps: step [1B], wherein the first main surface of the adhesive sheet described in item "I. Adhesive sheet" is attached to the surface of the first adhesive or to the surface of the gap formed by the third adhesive and the fourth adhesive; step [2B], wherein the first adhesive is inserted into the gap; and step [3B], wherein the adhesive sheet is heated to expand and cure the thermosetting adhesive layer, and the first adhesive, the third adhesive and the fourth adhesive are bonded through the expanded material of the adhesive sheet.

[0151] Figure 8 This is a process diagram illustrating another example of a method for manufacturing the article of the present invention. First, the first main surface (the side having the adhesive portion 2) of the adhesive sheet 10 described in section "I. Adhesive Sheet" is attached to both sides of the first adherend 51. Figure 8 (a), process [1B]). Next, in the gap S between the third adherend 53 and the fourth adherend 54, the first adherend 51 to which the adhesive piece 10 is attached is inserted. Figure 8 (b), process [2B]). Next, the adhesive sheet 10 is heated to form a thermally expandable thermosetting adhesive layer ( Figure 8 (c) Symbol 1) expands and cures, bonding the expanded adhesive sheet 10' to the third adherend 53 and the fourth adherend 54 with the second main surface (the side opposite to the surface with the adhesive portion 2). Figure 8 (c), process [3B]). At this time, the above-mentioned thermally expandable thermosetting adhesive layer (after expansion) is used. Figure 8 (c) symbol 1') fills the above-mentioned void S, while the expanded thermally expandable thermosetting adhesive layer ( Figure 8 The surface of symbol 1' in (c) is bonded to the third adherend 53 and the fourth adherend 54. Thus, an article 50 is obtained, wherein one side of the first adherend 51 is bonded to the third adherend 53, and the other side of the first adherend 51 is bonded to the fourth adherend 54 through the expanded adhesive sheet 10'.

[0152] The first adhered object is equivalent to an inserting member. Furthermore, the second adhered object with a gap, and the group of the third and fourth adhered objects constituting the gap, are equivalent to the inserted member. Examples of gaps in the second adhered object include holes, grooves, and openings formed in the adhered object. Furthermore, examples of gaps between the third and fourth adhered objects include separation spaces formed by the third and fourth adhered objects when they are separately configured, such as holes, grooves, and openings formed by the third and fourth adhered objects.

[0153] In processes [1A] and [1B], the first main surface of the adhesive sheet is attached to the surface of one of the adhered objects that becomes the insert member or the inserted member. Figure 7 , Figure 8 In process [1A] and [1B], the first main surface of the adhesive sheet is respectively attached to the two sides (opposite sides) of the first object to be bonded. However, the first main surface of the adhesive sheet can also be attached to at least one side of the first object to be bonded, or the first main surface of the adhesive sheet can be attached to more than three sides.

[0154] Furthermore, in processes [1A] and [1B], the first main surface of the adhesive sheet may be adhered to the first substrate. In process [1A], the first main surface of the adhesive sheet may also be adhered to the surface of the gap formed in the second substrate. On the other hand, in process [1B], it may also be adhered to the surface of the gap formed by the third and fourth substrates. In this case, the first main surface of the adhesive sheet may be adhered to one side of the surface of the gap, or it may be adhered to two or more sides.

[0155] When the first main surface of the adhesive sheet is adhered to two or more surfaces of the adhered object, a single adhesive sheet can be continuously adhered to multiple surfaces of the adhered object, or an adhesive sheet can be adhered to each surface of the adhered object separately. For example, when adhering an adhesive sheet to a first adhered object, the first main surfaces of different adhesive sheets can be adhered to two opposite surfaces of the first adhered object, and the first adhered object can be held between two adhesive sheets, or the adhesive sheet can be used to cover multiple surfaces of the first adhered object. Similarly, when adhering an adhesive sheet to the surface (surface of the adhered object) of a gap formed in a second adhered object or a gap formed by a third and fourth adhered object, the first main surfaces of different adhesive sheets can be adhered to two opposite surfaces of the gap, or the adhesive sheet can be used to cover multiple surfaces of the gap.

[0156] There are no particular limitations on the conditions under which the first main surface of the adhesive sheet is bonded to the surface of the object to be bonded. For example, it is preferable to bond at a temperature between room temperature (23°C) and 40°C, and more preferably at room temperature (23°C). Bonding at room temperature (23°C) allows for easy bonding by utilizing the initial adhesiveness of the first main surface of the adhesive sheet. Furthermore, it is preferable from the viewpoint of maintaining insertability by suppressing the increase in the initial adhesive force of the second main surface of the adhesive sheet.

[0157] In step [2A], the first adhesive is inserted into the gap formed in the second adhesive. Furthermore, in step [2B], the first adhesive is inserted into the gap between the third and fourth adhesives. In steps [2A] and [2B], the second main surface of the adhesive piece adhered to the adhesive is located at the outermost surface. Therefore, when the adhesive piece is adhered to the first adhesive, it is difficult for the adhesive piece to adhere to the surface of the gap and can be easily inserted. Even if it adheres, the adhesive piece is difficult to peel off due to the force applied during insertion, thus maintaining temporary fixation and improving insertability. Similarly, when the adhesive piece is adhered to the surface of the gap, it is also difficult for the adhesive piece to adhere to the first adhesive and can be easily inserted. Even if it adheres, the adhesive piece is difficult to peel off due to the force applied during insertion, thus maintaining temporary fixation and improving insertability.

[0158] In processes [3A] and [3B], while the first adherend is inserted into the gap, the adhesive sheet is heated to cause the thermosetting adhesive layer to expand and cure. Heating can be applied directly to the thermosetting adhesive layer of the adhesive sheet, or to the entire assembly including the adherend. The heating method can be non-contact or contact-type, and can utilize methods such as hot air heating, heating based on contact with an electric heater, heating based on light irradiation from infrared heaters, halogen heaters, induction heating, or similar methods.

[0159] The heating temperature in steps [3A] and [3B] can be set to a temperature at which the thermosetting adhesive layer can expand and cure. Preferably, this temperature corresponds to the curing temperature of the thermosetting adhesive layer and the expansion temperature (expansion start temperature) of the expanding agent, and is preferably above the expansion temperature of the expanding agent. Specifically, it is preferably 80°C to 350°C, more preferably 100°C to 250°C, and even more preferably 150°C to 200°C.

[0160] Furthermore, the heating time in processes [3A] and [3B] can be set to a time during which the thermally expandable thermosetting adhesive layer can expand and cure, preferably an expansion time or longer. Specifically, it is preferably 5 to 300 minutes, more preferably 10 to 200 minutes, and even more preferably 20 to 100 minutes. By setting the heating time as described above, thermal damage to the adhered materials can be appropriately suppressed and a firm bond between the components can be achieved.

[0161] In processes [3A] and [3B], the adhesive sheet expands by heating within the gap, thereby filling the gap. In process [3A], the first and second adherends are bonded together through the expanded adhesive sheet. In process [3B], the first adherend, the third adherend, and the fourth adherend are bonded together. Within the gap, the adhesive sheet expands upon heating, allowing its second main surface to contact the substrate without the adhesive sheet. At this time, the expanded material of the thermosetting adhesive layer constituting the first and second main surfaces of the adhesive sheet cures upon heating, exhibiting adhesive force. Therefore, the insert member (first substrate) can be firmly bonded to the inserted member (second substrate) or the aforementioned third and fourth substrates. Furthermore, the expanded material of the thermosetting adhesive layer is a thermosetting material with high heat resistance, thus maintaining high adhesive force even at high temperatures.

[0162] The article obtained by the manufacturing method of the present invention is not particularly limited, and examples include motors mounted in hybrid vehicles. Specifically, it can be manufactured by pre-bonding a first main surface of an adhesive sheet to a part such as a magnet, inserting and placing the adhesive sheet into the gap of the core member constituting the motor, and then heating the adhesive sheet to expand and cure the thermosetting adhesive layer. Therefore, the manufacturing method of the article of the present invention is useful as a method for manufacturing motors.

[0163] This disclosure is not limited to the embodiments described above. The embodiments described above are illustrative and may have a structure that is substantially the same as the technical concept described in the scope of this disclosure, and perform the same effect. Regardless of the structure, all are included within the technical scope of this disclosure. Example

[0164] The present invention will be specifically illustrated below through examples.

[0165] (Preparation Example 1) <Preparation of a thermosetting adhesive composition (a-1) with thermal expansion properties> 35 parts by weight of epoxy resin 1 (BPA type, epoxy equivalent 8000 g / eq., solid (25°C), softening point above 200°C), 7 parts by weight of epoxy resin 2 (modified BPA type, epoxy equivalent 400 g / eq., 1.4 million mPa·s (25°C)), 58 parts by weight of epoxy resin 3 (dicyclopentadiene type, epoxy equivalent 280 g / eq., solid (25°C), softening point 100°C), 3.8 parts by weight of curing agent 1 (dicyandiamide, solid), 3 parts by weight of curing agent 2 (2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-triazine isocyanuric acid adduct, solid), and 1 part by weight of expanding agent 1 (thermal expansion capsule, expansion start temperature 125°C, solid) were dissolved in 60 parts by weight of methyl ethyl ketone to prepare a thermosetting adhesive composition (a-1).

[0166] (Preparation Example 2) <Preparation of thermosetting adhesive composition (a-2) with thermal expansion> Instead of epoxy resin 2, epoxy resin 4 (BPA type, epoxy equivalent 188 g / eq., 11,000 mPa·s (25°C)) was set at 7 parts by weight; instead of epoxy resin 3, epoxy resin 5 (modified phenolic varnish type, epoxy equivalent 160 g / eq., semi-solid (25°C)) was set at 58 parts by weight; and the amount of curing agent 1 was changed from 3.8 parts by weight to 6.7 parts by weight. Otherwise, a thermosetting adhesive composition (a-2) was prepared using the same method as in Preparation Example 1.

[0167] (Preparation Example 3) <Preparation of thermosetting adhesive composition (a-3) with thermal expansion> The amount of epoxy resin 1 used was changed from 35 parts by mass to 25 parts by mass, the amount of epoxy resin 2 used was changed from 7 parts by mass to 17 parts by mass, and the amount of curing agent 1 used was changed from 3.8 parts by mass to 4.1 parts by mass. Otherwise, a thermosetting adhesive composition with thermal expansion was prepared by the same method as in Preparation Example 1 (a-3).

[0168] (Preparation Example 4) <Preparation of Adhesive (b-1)> 97.98 parts by mass of n-butyl acrylate, 2 parts by mass of acrylic acid, and 0.02 parts by mass of 4-hydroxybutyl acrylate were subjected to solution polymerization in ethyl acetate solution at 90°C for 6 hours using 0.3 parts by mass of azobisisobutyronitrile as a polymerization initiator, thereby obtaining an acrylic polymer with a weight average molecular weight of 500,000.

[0169] Relative to 100 parts by weight of the aforementioned acrylic polymer, 5 parts by weight of "D-135" (manufactured by Arakawa Chemical Industry Co., Ltd., polymeric rosin ester), 20 parts by weight of "KE-100" (manufactured by Arakawa Chemical Industry Co., Ltd., disproportionated rosin ester), and 25 parts by weight of "FTR6100" (manufactured by Mitsui Chemicals Co., Ltd., petroleum resin) were mixed, and ethyl acetate was further added to obtain an adhesive solution with a solid content adjusted to 40% by weight.

[0170] The above adhesive solution was mixed with 1.2 parts by weight of "NC40" (manufactured by DIC Corporation, an isocyanate-based crosslinking agent) and stirred to obtain adhesive (b-1).

[0171] The adhesive layer obtained using the above adhesive (b-1) has a peak tanδ temperature of 0°C and a gel fraction of 20% by mass.

[0172] (Example 1) Using a rod-shaped metal coater, the thermosetting adhesive composition (a-1) obtained in Preparation Example 1 was coated onto the surface of a release liner (a 50 μm thick polyethylene terephthalate film with one side peeled off using an organosilicon compound) to a dried thickness of 62 μm. The coating was then dried in a dryer at 85°C for 5 minutes, thereby obtaining a sheet-like thermosetting adhesive layer (A-1) with a thickness of 62 μm formed on one side of the release liner. Two of these sheets were fabricated.

[0173] In the two sheets obtained above, a 25 μm thick polyimide film is overlapped on the surface of the thermosetting adhesive layer (A-1) of one sheet, and is attached in a laminator preheated to 50°C with a linear pressure of 3 N / mm, and a polyimide film is laminated on one side of the thermosetting adhesive layer (A-1). Next, another sheet of the aforementioned thermosetting adhesive layer (A-1) is overlapped on the polyimide film side of the above-mentioned laminate, and then bonded in a laminator preheated to 50°C with a linear pressure of 3 N / mm, thereby obtaining an adhesive sheet with a thickness of 149 μm (excluding the thickness of the release liner, the same applies below) of thermosetting adhesive layer (A-1) laminated on both sides of the polyimide film.

[0174] Next, the adhesive (b-1) was dot-printed onto the surface of the release liner (a 25 μm thick polyethylene terephthalate film with one side treated by a silicone compound) using a gravure coating machine and dried at 85°C for 2 minutes, thereby forming multiple 3 μm thick films, each with an area of ​​0.5 mm. 2 The adhesive portion (B-1) is a roughly circular island shape. The shortest distance between any adhesive portion (b1) selected from two or more adhesive portions (B-1) and the adhesive portion (b2) adjacent to the aforementioned adhesive portion (b1) is 0.2 mm.

[0175] Next, the release liner on one side of the adhesive sheet (x-1) is peeled off, and a thermosetting adhesive layer (A-1) of the adhesive sheet (x-1) is overlapped with the adhesive part (B-1). The adhesive sheet (X-1) is then attached using a laminator at 23°C with a linear pressure of 3 N / mm to obtain the adhesive sheet (X-1).

[0176] The total thickness of the aforementioned adhesive sheet (X-1) is 152 μm, and the aforementioned adhesive portion (B-1) is laminated on one surface of the aforementioned thermosetting adhesive layer (A-1). That is, as... Figure 1As illustrated in (a), in the thickness direction of the adhesive sheet (X-1), the first surface of the adhesive portion (B-1) is located further outward than the first main surface of a thermosetting adhesive layer (A-1), and the second surface of the adhesive portion (B-1) is in contact with the first main surface of a thermosetting adhesive layer (A-1). The total area of ​​the aforementioned adhesive portions (B-1) accounts for 60% of the area of ​​the first main surface of the adhesive sheet (X-1).

[0177] In addition, the bonded sheet (X-1) after heating at 150°C for 60 minutes, such as Figure 2 (a) As illustrated, in the thickness direction, the first surface of the adhesive portion (B-1) is located at the same position as the first main surface of a thermosetting adhesive layer (A-1), and the second surface of the adhesive portion (B-1) is located between the first and second main surfaces of the thermosetting adhesive layer (A-1). After curing (expanding) at 150°C for 60 minutes, the thermosetting adhesive layer (A-1) in the adhesive sheet (X-1) exhibits an expansion rate of 390% and a glass transition temperature of 157°C. It should be noted that the expansion rate and glass transition temperature were measured using the method described in section "I. Adhesive Sheet" above. The same applies to the following examples and comparative examples.

[0178] (Example 2) The thermally expandable thermosetting adhesive layer (A-1) of the above-mentioned adhesive sheet (x-1) and the above-mentioned adhesive portion (B-1) are overlapped, and the lamination temperature during attachment is changed from 23°C to 50°C. Otherwise, the adhesive sheet (X-2) is obtained using the same method as in Example 1. The shortest distance between any adhesive portion (b1) selected from two or more adhesive portions (B-1) and the adhesive portion (b2) adjacent to the above-mentioned adhesive portion (b1) is 0.2 mm.

[0179] The total thickness of the aforementioned adhesive sheet (X-2) is 149 μm, and the aforementioned adhesive portion (B-1) is embedded in one side of the aforementioned thermosetting adhesive layer (A-1). That is, as... Figure 3 As illustrated, in the thickness direction of the adhesive sheet (X-2), the first surface of the adhesive portion (B-1) is located at the same position as the first main surface of a thermosetting adhesive layer (A-1), and the second surface of the adhesive portion (B-1) is located between the first and second main surfaces of the thermosetting adhesive layer (A-1). The total area of ​​the aforementioned adhesive portions (B-1) accounts for 60% of the area of ​​the first main surface of the adhesive sheet (X-2).

[0180] In addition, the bonded sheet (X-2) after heating at 150°C for 60 minutes, such as Figure 2(a) As illustrated, in the thickness direction, the first surface of the adhesive portion (B-1) is located at the same position as the first main surface of a thermosetting adhesive layer (A-1), and the second surface of the adhesive portion (B-1) is located between the first and second main surfaces of the thermosetting adhesive layer (A-1). After curing (expanding) at 150°C for 60 minutes, the thermosetting adhesive layer (A-1) in the adhesive sheet (X-2) has an expansion rate of 390% and a glass transition temperature of 157°C.

[0181] (Example 3) Multiple layers, each 3 μm thick and with an area of ​​0.3 mm, are formed on the release liner. 2 A generally circular adhesive portion (B-2) is used instead of the aforementioned adhesive portion (B-1). A thermosetting adhesive layer (A-1) of the aforementioned adhesive sheet (x-1) is overlapped with the aforementioned adhesive portion (B-2). Otherwise, the adhesive sheet (X-3) is obtained by the same method as in Example 1. The shortest distance between any adhesive portion (b1) selected from two or more adhesive portions (B-2) and the adhesive portion (b2) adjacent to the aforementioned adhesive portion (b1) is 0.2 mm.

[0182] The total thickness of the aforementioned adhesive sheet (X-3) is 152 μm, and the aforementioned adhesive portion (B-2) is laminated on one surface of the aforementioned thermosetting adhesive layer (A-1). That is, as... Figure 1 (a) As illustrated, in the thickness direction of the adhesive sheet (X-3), the first surface of the adhesive portion (B-2) is located further outward than the first main surface of a thermally expanding thermosetting adhesive layer (A-1), and the second main surface of the adhesive portion (B-2) is in contact with the first main surface of a thermally expanding thermosetting adhesive layer (A-1). The total area of ​​the aforementioned adhesive portion (B-2) accounts for 37% of the area of ​​the first main surface of the aforementioned adhesive sheet (X-3).

[0183] In addition, the bonded sheet (X-3) after heating at 150°C for 60 minutes, such as Figure 2 (a) As illustrated, in the thickness direction, the first surface of the adhesive portion (B-2) is located at the same position as the first main surface of a thermosetting adhesive layer (A-1), and the second surface of the adhesive portion (B-2) is located between the first and second main surfaces of the thermosetting adhesive layer (A-1). After curing (expanding) at 150°C for 60 minutes, the thermosetting adhesive layer (A-1) in the adhesive sheet (X-3) has an expansion rate of 390% and a glass transition temperature of 157°C.

[0184] (Example 4) Instead of the aforementioned sheet-like thermosetting adhesive layer (A-1), two sheet-like thermosetting adhesive layers (A-2) with a thickness changed from 62 μm to 75 μm were formed on one side of the release liner. The other thermosetting adhesive layer (A-2) was overlapped on the surface of one layer and bonded using a laminator preheated to 50°C at a linear pressure of 3 N / mm, thereby obtaining an adhesive sheet (x-4) with a thickness of 150 μm formed by laminating the thermosetting adhesive layers (A-2). Adhesive sheet (x-4) was used instead of adhesive sheet (x-1), and otherwise obtained by the same method as in Example 1.

[0185] The total thickness of the adhesive sheet (X-4) is 153 μm, and the aforementioned adhesive portion (B-1) is laminated on one side of the aforementioned thermosetting adhesive layer (A-2). That is, as... Figure 1 (a) As illustrated, in the thickness direction of the adhesive sheet (X-4), the first surface of the adhesive portion (B-1) is located further outward than the first main surface of a thermally expanding thermosetting adhesive layer (A-2), and the second surface of the adhesive portion (B-1) is in contact with the first main surface of a thermally expanding thermosetting adhesive layer (A-2). The total area of ​​the aforementioned adhesive portion (B-1) accounts for 60% of the area of ​​the first main surface of the adhesive sheet (X-4).

[0186] In addition, the bonded sheet (X-4) after heating at 150°C for 60 minutes, such as Figure 2 (a) As illustrated, in the thickness direction, the first surface of the adhesive portion (B-1) is located at the same position as the first main surface of a thermosetting adhesive layer (A-2), and the second surface of the adhesive portion (B-1) is located between the first and second main surfaces of the thermosetting adhesive layer (A-2). After curing (expanding) at 150°C for 60 minutes, the thermosetting adhesive layer (A-2) in the adhesive sheet (X-4) has an expansion rate of 390% and a glass transition temperature of 157°C.

[0187] (Example 5) Using a thermosetting adhesive composition (a-2) instead of a thermosetting adhesive composition (a-1), two thermosetting adhesive layers (A-3) are formed on one side of a release liner sheet. On both sides of the polyimide film, the thermosetting adhesive layer (A-3) is used instead of the thermosetting adhesive layer (A-1) and is laminated on both sides of the polyimide film. Otherwise, the adhesive sheet (X-5) is obtained by the same method as in Example 1.

[0188] The total thickness of the adhesive sheet (X-5) is 152 μm, and the aforementioned adhesive portion (B-1) is laminated on one side of the aforementioned thermosetting adhesive layer (A-3). That is, as... Figure 1 (a) As illustrated, in the thickness direction of the adhesive sheet (X-5), the first surface of the adhesive portion (B-1) is located further outward than the first main surface of a thermosetting adhesive layer (A-3), and the second surface of the adhesive portion (B-1) is in contact with the first main surface of a thermosetting adhesive layer (A-3). The total area of ​​the aforementioned adhesive portions (B-1) accounts for 60% of the area of ​​the first main surface of the adhesive sheet (X-5).

[0189] In addition, the bonded sheet (X-5) after heating at 150°C for 60 minutes, such as Figure 2 (a) As illustrated, in the thickness direction, the first surface of the adhesive portion (B-1) is located at the same position as the first main surface of a thermosetting adhesive layer (A-3), and the second surface of the adhesive portion (B-1) is located between the first and second main surfaces of the thermosetting adhesive layer (A-3). After curing (expanding) at 150°C for 60 minutes, the thermosetting adhesive layer (A-3) in the adhesive sheet (X-5) has an expansion rate of 415% and a glass transition temperature of 172°C.

[0190] (Example 6) Two thermosetting adhesive layers (A-4) are formed on one side of the release liner using a thermosetting adhesive composition (a-3) instead of a thermosetting adhesive composition (a-1). The thermosetting adhesive layer (A-4) is laminated on both sides of the polyimide film instead of a thermosetting adhesive layer (A-1). Otherwise, the adhesive sheet (X-6) is obtained by the same method as in Example 1.

[0191] The total thickness of the aforementioned adhesive sheet (X-6) is 152 μm, and the aforementioned adhesive portion (B-1) is laminated on one side of the aforementioned thermosetting adhesive layer (A-4). That is, as... Figure 1 (a) As illustrated, in the thickness direction of the adhesive sheet (X-6), the first surface of the adhesive portion (B-1) is located further outward than the first main surface of a thermosetting adhesive layer (A-4), and the second surface of the adhesive portion (B-1) is in contact with the first main surface of a thermosetting adhesive layer (A-4). The total area of ​​the aforementioned adhesive portions (B-1) accounts for 60% of the area of ​​the first main surface of the adhesive sheet (X-6).

[0192] In addition, the bonded sheet (X-6) after heating at 150°C for 60 minutes, such as Figure 2(a) As illustrated, in the thickness direction, the first surface of the adhesive portion (B-1) is located at the same position as the first main surface of a thermosetting adhesive layer (A-4), and the second surface of the adhesive portion (B-1) is located between the first and second main surfaces of the thermosetting adhesive layer (A-4). After curing (expanding) at 150°C for 60 minutes, the thermosetting adhesive layer (A-4) in the adhesive sheet (X-6) has an expansion rate of 424% and a glass transition temperature of 145°C.

[0193] (Comparative Example 1) On the surface of the release liner (a 25 μm thick polyethylene terephthalate film with one side treated by a silicone compound), the adhesive (b-1) is applied to the entire surface using a gravure coating machine and then dried at 85°C for 2 minutes, thereby obtaining a sheet material with a 3 μm thick sheet-like adhesive layer (B'-1) formed on one side of the release liner. Using the adhesive layer (B'-1) instead of the adhesive portion (B-1), an adhesive sheet (X'-1) is obtained by the same method as in Example 1.

[0194] The total thickness of the adhesive sheet (X'-1) is 152 μm, and the adhesive layer (B'-1) is laminated on one side of the thermosetting adhesive layer (A-1). On the surface of the adhesive sheet (X'-1), the adhesive layer (B'-1) side is designated as the first main surface, and the thermosetting adhesive layer (A-1) side is designated as the second main surface.

[0195] The aforementioned adhesive layer (B'-1) is non-patterned and is disposed on a single, entire surface of the thermosetting adhesive layer (A-1). Therefore, the total area of ​​the aforementioned adhesive layer (B'-1) accounts for 100% of the area of ​​the first main surface of the adhesive sheet (X'-1). Furthermore, the expansion rate and glass transition temperature of the cured (expanded) thermosetting adhesive layer (A-1) in the adhesive sheet (X'-1) after heating at 150°C for 60 minutes are the same as those of the thermosetting adhesive layer (A-1) in Example 1.

[0196] (Comparative Example 2) The adhesive sheet (x-1) obtained in Example 1 above was replaced with adhesive sheet (X'-2) for evaluation.

[0197] The total thickness of the aforementioned adhesive sheet (X'-2) is 149 μm.

[0198] The aforementioned adhesive sheet (X′-2) does not have an adhesive portion; therefore, the total area of ​​the adhesive portion accounts for 0% of the area of ​​a single side of the adhesive sheet (X′-2). The surface of the adhesive sheet (X′-2) with one side of the thermosetting adhesive layer (A-1) is designated as the first main surface, and the surface with the other side of the thermosetting adhesive layer (A-1) is designated as the second main surface. After heating at 150°C for 60 minutes, the expansion rate and glass transition temperature of the cured (expanded) thermosetting adhesive layer (A-1) in the adhesive sheet (X′-2) are the same as those of the thermosetting adhesive layer (A-1) in Example 1.

[0199] [Method for determining the shear bond strength of thermosetting adhesive layers before heating] The release liner with thermally expandable thermosetting adhesive layers (A-1) to (A-4) obtained in the above embodiments and comparative examples was cut into 10mm × 10mm pieces and used as test samples. Two smooth aluminum plates with a width of 15mm × length of 70mm × thickness of 0.5mm were degreased, and the side of the aluminum plate with the thermally expandable thermosetting adhesive layer of the above test sample was pressed together using a 2kg hand roller at 23°C.

[0200] Next, the release liner of the test sample pressed against the aluminum plate was peeled off, and another aluminum plate with a smooth, degreased surface was overlapped on the upper surface of the test sample. The plates were then pressed together at 23°C for 10 seconds under a load of 0.5 MPa. After being placed at 23°C for 30 minutes, the ends of the two aluminum plates were clamped, and the shear force was measured using a Tensilon tensile testing machine [manufactured by A&D Corporation, model: RTM-100] at a tensile speed of 10 mm / min in a 180-degree direction.

[0201] [Method for measuring the shear adhesion strength of the bonded area] The release liner with adhesive portions (B-1) to (B-2) obtained in the above embodiments and comparative examples was cut into 10mm × 10mm pieces and used as test samples. Two smooth aluminum plates with a width of 15mm × length of 70mm × thickness of 0.5mm were degreased, and the adhesive portion side of the above test sample was fitted to the upper surface of one aluminum plate. The plates were then pressed together at 23°C using a 2kg hand roller.

[0202] Next, the release liner of the test sample pressed against the aluminum plate was peeled off, and another aluminum plate with a smooth, degreased surface was overlapped on the upper surface of the test sample. The plates were then pressed together at 23°C for 10 seconds under a load of 0.5 MPa. After being placed at 23°C for 30 minutes, the ends of the two aluminum plates were clamped, and the shear force was measured using a Tensilon tensile testing machine [manufactured by A&D Corporation, model: RTM-100] at a tensile speed of 10 mm / min in a 180-degree direction.

[0203] [Determination of shear adhesion strength on one and both sides of the adhesive sheet before heating] The adhesive sheets from the above embodiments and comparative examples were cut into 10mm × 10mm pieces to obtain test samples. Two smooth aluminum plates with a width of 15mm × length of 70mm × thickness of 0.5mm were degreased. A two-component, room-temperature curing acrylic adhesive (Metal Lock, manufactured by Cemedine) was applied to the upper surface of one aluminum plate as a strong adhesive for fixing the test sample. The release liner on the second main side of the test sample was peeled off, and the second main side of the test sample was overlapped onto the aluminum plate through the aforementioned strong adhesive. The sample was pressed at 23°C using a 2kg hand roller. Next, the release liner on the first main side of the test sample pressed onto the aluminum plate was peeled off, and another degreased aluminum plate with a smooth surface was overlapped on the upper surface of the test sample. The sample was then pressed at 23°C for 10 seconds with a load of 0.5MPa. After placing the plates at 23°C for 5 minutes, clamp the ends of the two aluminum plates and use a Tensilon tensile testing machine [manufactured by A&D Corporation, model: RTM-100] to measure the shear force in a 180-degree direction at a tensile speed of 10 mm / min. This shear force is taken as the shear bond force of the first major surface of the bonded sheet.

[0204] In addition, the first main surface of the test sample with the release liner peeled off was pressed against an aluminum plate through the aforementioned strong adhesive, and another aluminum plate was pressed against the second main surface of the test sample. Otherwise, the same measurement method as described above was performed to measure the adhesive force in the shear direction. This adhesive force was then taken as the shear adhesive force of the second main surface of the adhesive sheet.

[0205] [Evaluation method for the temporary fixation of components by adhesive tape] The adhesive sheets (X-1) to (X-6) and (X'-1) to (X'-2) obtained in the above embodiments and comparative examples were cut into 15mm × 15mm sizes and used as test samples. Next, the release liner on the first main surface (the side with the adhesive portion or adhesive layer) of the test sample was peeled off and overlapped onto the center of a degreased, smooth SUS plate with a width of 40mm × length of 50mm × thickness of 3mm. The sample was then pressed at 23°C for 10 seconds under a load of 0.5MPa to fix it. Regarding the adhesive sheet (X'-2) prepared in Comparative Example 2, the release liner on one main surface was peeled off, pressed onto the SUS plate, and fixed.

[0206] Then, at 23°C, the SUS board was erected at a 90° angle relative to the floor. The SUS board was then lifted so that the test sample attached to the SUS board was 15 cm above the floor, and then dropped vertically. This operation was repeated 10 times. The offset caused by the drop of the test sample was then measured, and the temporary fixation of the component was evaluated according to the following criteria. (Judgment Criteria) ◎: The offset of the test sample is 0 mm. 〇: The offset of the test sample is less than 1mm. △: The offset of the test sample is greater than 1 mm. ×: The test sample was peeled off from the SUS plate.

[0207] [Methods for evaluating the insertability of adhesive sheets in components] The adhesive sheets (X-1) to (X-6) and (X′-1) to (X′-2) obtained in the above embodiments and comparative examples were each cut to a size of 15mm × 15mm. Next, the release liner on the first main surface (the side with the adhesive portion or adhesive layer) of the adhesive sheet was peeled off and overlapped onto the center of a degreased, smooth SUS plate with a width of 30mm × length of 30mm × thickness of 1mm. The adhesive sheet was then pressed at 23°C for 10 seconds under a load of 0.5MPa to fix it. Regarding the adhesive sheet (X′-2) produced in Comparative Example 2, the release liner on one main surface was peeled off, pressed onto the SUS plate, and fixed. Then, the material from which the other release liner of the adhesive sheet was removed was used as a test sample.

[0208] Next, prepare two smooth glass plates, each 70mm wide, 50mm long, and 1.5mm thick. Place them side-by-side with a 60mm gap between them on one glass plate (C1) and glue two spacers, each 5mm wide and 50mm long. Then, overlap another glass plate (C2) on top of the spacers and glue it to the spacers, thereby creating a gap consisting of two glass plates and two spacers.

[0209] Then, the test sample is erected at a 90° angle relative to the floor and vertically inserted through the gap consisting of two pieces of glass and two spacers. The thickness of the spacers through which the test sample can pass without being bonded to the glass is measured. The insertability of the test sample into the component is evaluated according to the following criteria. (Judgment Criteria) ◎: The test sample passed when the thickness of the spacer was increased by 50 μm relative to the total thickness of the adhesive sheet and the SUS plate. 〇: The test sample failed when the thickness of the spacer was increased by 50 μm relative to the total thickness of the adhesive sheet and SUS plate, but passed when the thickness was increased by 75 μm. △: The test sample failed when the thickness of the spacer was increased by 75 μm relative to the total thickness of the adhesive sheet and SUS plate, but passed when the thickness was increased by 100 μm. ×: The test sample could not pass through when the thickness of the spacer was increased by 100 μm relative to the total thickness of the adhesive sheet and the SUS plate, or the adhesive sheet peeled off from the SUS plate when it passed through.

[0210] [Method for determining the shear bond strength of bonded sheets after heating (expansion)] Two smooth aluminum plates 51 and 52, each 15mm wide, 70mm long, and 0.5mm thick, are degreased. Figure 9 As shown, at the end of the upper surface of an aluminum plate 51, two spacers 53, spaced 12 mm apart and 5 mm wide, are arranged in parallel and bonded together. The spacers 53 are constructed using a method where the total thickness of the adhesive tape used for bonding to the spacers 53 is increased by 150 μm relative to the total thickness of the adhesive sheet. Next, on the upper surface side of the aluminum plate 51 and between the two spacers 53, the release liner on the first main surface (the side with the adhesive portion or adhesive layer) of the adhesive sheet is peeled off and attached to the adhesive sheets (X-1) to (X-6) and (X'-1) to (X'-2) of the embodiments and comparative examples, which are pre-cut to 10 mm × 10 mm in size. Figure 9 (10) was pressed using a 2kg hand roller. Regarding the adhesive sheet (X′-2) produced in Comparative Example 2 above, the release liner on one main side was peeled off and attached, and then pressed using a 2kg hand roller.

[0211] Next, the release liner on the second main surface (thermo-expandable thermosetting adhesive layer) side of the adhesive sheet 10 is peeled off, and another aluminum plate 52 (15mm wide × 70mm long × 0.5mm thick), with a smooth surface after degreasing treatment, is placed on the second main surface (upper surface of the thermo-expandable thermosetting adhesive layer) of the adhesive sheet 10, and they are fixed with clips. Regarding the adhesive sheet (X′-2) produced in Comparative Example 2 above, the release liner on the other main surface side is peeled off and placed on another aluminum plate 52. The fixed sheet is heated at 150°C for 60 minutes and then cooled at 23°C for 30 minutes. Next, the material from which the clamps were removed was used as a test sample. The ends of the two aluminum plates 51 and 52 were clamped together, and the shear force was measured in the tensile direction at 23°C and 150°C when the tensile test was performed at 10 mm / min in the 180-degree direction.

[0212] The evaluation results are shown in the table below.

[0213] [Table 1]

[0214] [Table 2]

[0215] The adhesive sheets of Examples 1-6 exhibited good temporary fixation and insertability before expansion, and high adhesive strength at both room temperature and high temperature after expansion. On the other hand, in Comparative Example 1, where the adhesive portion on the first main surface of the adhesive sheet was not patterned (an adhesive layer was provided on one entire side of the thermosetting adhesive layer), the temporary fixation and insertability before expansion were good, but the adhesive strength at both room temperature and high temperature after expansion was lower than that of the adhesive sheets of the Examples, particularly the high-temperature adhesive strength was poor. Furthermore, in Comparative Example 2, where no adhesive portion was provided on the surface of the thermosetting adhesive layer on the first main surface of the adhesive sheet, the adhesive strength at both room temperature and high temperature after expansion was as high as that of the adhesive sheets of the Examples. However, without achieving the temporary fixation before expansion, the adhesive sheet peeled off when the test sample passed through, thus hindering the insertion of the test sample and preventing the achievement of good insertability. Symbol Explanation

[0216] 1, 1A, 1B... Thermosetting adhesive layers with thermal expansion properties 1'...The expanded thermosetting adhesive layer after expansion (the expanded product of the thermosetting adhesive layer) 2… Adhesive section 3…Intermediate layer 10… Adhesive sheet 10'... Expanded adhesive sheet (expanded adhesive sheet material) Z-Z'…Thickness direction of the adhesive sheet a1, a11, a12… First main surfaces of thermally expandable thermosetting adhesive layers a2, a21, a22… Second main surfaces of thermally expandable thermosetting adhesive layers b1…First surface of the adhesive part b2…Second side of the adhesive part 50… items

Claims

1. An adhesive sheet, characterized in that, The adhesive sheet has a first principal surface and a second principal surface that are opposite each other. When the adhesive sheet has a thermosetting adhesive layer, the first main surface of the adhesive sheet is composed of the thermosetting adhesive layer and a plurality of adhesive portions patterned on the first main surface of the thermosetting adhesive layer. The second main surface of the adhesive sheet is composed of the thermally expandable thermosetting adhesive layer that constitutes the first main surface of the adhesive sheet. When the adhesive sheet has two or more thermosetting adhesive layers, the first main surface of the adhesive sheet is composed of a thermosetting adhesive layer located on the outermost side in the thickness direction of the adhesive sheet and a plurality of adhesive portions patterned on the first main surface of the thermosetting adhesive layer. The second main surface of the adhesive sheet is composed of a thermosetting adhesive layer that is different from the thermosetting adhesive layer constituting the first main surface of the adhesive sheet and located on the other outermost side in the thickness direction of the adhesive sheet. The thermosetting adhesive layer constituting the second main surface of the adhesive sheet contains less than 20% by mass of a liquid thermosetting resin with a viscosity of less than 3 million mPa·sec at 25°C in all resin components of the thermosetting adhesive layer.

2. The adhesive sheet according to claim 1, wherein, The shear bond strength of the first main surface of the adhesive sheet is higher than that of the second main surface.

3. The adhesive sheet according to claim 1 or 2, wherein, The adhesive portion has a first surface and a second surface on its opposite side. Before expansion, in the thickness direction of the adhesive sheet, the first surface of the adhesive portion is located outside the first main surface of the thermosetting adhesive layer on which the adhesive portion is provided, and the second surface of the adhesive portion is in contact with the first main surface of the thermosetting adhesive layer on which the adhesive portion is provided, or is located between the first main surface of the thermosetting adhesive layer and the second main surface on its opposite side. After expansion, in the thickness direction of the adhesive sheet, the first surface of the adhesive portion is located at the same position as the first main surface of the expanded thermosetting adhesive layer with the adhesive portion, or between the first main surface and the second main surface on the opposite side, and the second surface of the adhesive portion is located between the first main surface and the second main surface on the opposite side of the expanded thermosetting adhesive layer with the adhesive portion.

4. The adhesive sheet according to claim 1 or 2, wherein, The adhesive portion has a first surface and a second surface on its opposite side. Before expansion, in the thickness direction of the adhesive sheet, the first surface of the adhesive portion is located at the same position as the first main surface of the thermosetting adhesive layer on which the adhesive portion is provided, and the second surface of the adhesive portion is located between the first main surface of the thermosetting adhesive layer on which the adhesive portion is provided and the second main surface on its opposite side. After expansion, in the thickness direction of the adhesive sheet, the first surface of the adhesive portion is located at the same position as the first main surface of the expanded thermosetting adhesive layer with the adhesive portion, or between the first main surface and the second main surface on the opposite side, and the second surface of the adhesive portion is located between the first main surface and the second main surface on the opposite side of the expanded thermosetting adhesive layer with the adhesive portion.

5. The adhesive sheet according to claim 1 or 2, wherein, The shear bond strength of the first main surface of the adhesive sheet is above 0.2 MPa.

6. The adhesive sheet according to claim 1 or 2, wherein, The shear bond strength of the second main surface of the adhesive sheet is less than 0.5 MPa.

7. The adhesive sheet according to claim 1 or 2, wherein, When viewed from above, the total area of ​​the plurality of adhesive portions accounts for more than 20% and less than 80% of the first main surface of the adhesive sheet before expansion.

8. The adhesive sheet according to claim 1 or 2, wherein, The gel fraction of the adhesive portion is less than 60% by mass.

9. The adhesive sheet according to claim 1 or 2, wherein, The adhesive part uses acrylic resin as its main component.

10. The adhesive sheet according to claim 1 or 2, wherein, The top view of the adhesive part is circular, quadrilateral, or hexagonal.

11. The adhesive sheet according to claim 1 or 2, wherein, The glass transition temperature of the thermally expandable thermosetting adhesive layer constituting the second main surface of the adhesive sheet after expansion is above 80°C.

12. An article characterized in that, The article has a first adhesive and a second adhesive. The second adhered material has gaps. The first adhesive is disposed within the gap of the second adhesive. Within the gap, the first adherend and the second adherend are bonded together with the expansion of the adhesive sheet according to any one of claims 1 to 11.

13. An article characterized in that, The article has a first adhesive, a third adhesive, and a fourth adhesive. There is a gap between the third and fourth adhered materials. The first adhesive is disposed within the gap. Within the gap, the first adherend and the third adherend, as well as the first adherend and the fourth adherend, are bonded together with the expansion of the adhesive sheet according to any one of claims 1 to 11.

14. A method for manufacturing an article, characterized in that, It has the following processes: Step [1A], wherein the first main surface of the adhesive sheet according to any one of claims 1 to 11 is adhered to the surface of the first adherend or to the surface of the gap formed in the second adherend; Step [2A], wherein the first adhesive is inserted into the gap; and Step [3A], wherein the adhesive sheet is heated to cause the thermally expandable thermosetting adhesive layer to expand and cure, and the first substrate and the second substrate are bonded together through the expanded material of the adhesive sheet.

15. A method for manufacturing an article, characterized in that, It has the following processes: Step [1B], wherein the first main surface of the adhesive sheet according to any one of claims 1 to 11 is adhered to the surface of the first adhered object or to the surface of the gap formed by the third and fourth adhered objects; Step [2B], wherein the first adhesive is inserted into the gap; and Step [3B], wherein the adhesive sheet is heated to expand and cure the thermosetting adhesive layer, and the first adherend is bonded to the third adherend and the fourth adherend through the expanded material of the adhesive sheet.

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