Adhesive sheet, and article and method for manufacturing article

Abstract

The present invention provides a heat-expandable adhesive sheet or the like which can give temporary fixation at normal temperature before expansion, easy insertion when a member is inserted into a gap in another member, sufficient filling of the gap after expansion, and excellent adhesive strength in a high-temperature environment, and firmly bonds the members to each other. The present invention provides an adhesive sheet having opposite first and second surfaces, the first surface being composed of a heat-expandable thermosetting adhesive layer A, the second surface being composed of a heat-expandable thermosetting adhesive layer B which is different from the heat-expandable thermosetting adhesive layer A, the heat-expandable thermosetting adhesive layer B being laminated on one surface of the heat-expandable thermosetting adhesive layer A directly or through another layer, the shear adhesive strength of the first surface being higher than that of the second surface, and the expansion rates in the thickness direction of the heat-expandable thermosetting adhesive layer A and the heat-expandable thermosetting adhesive layer B after heating at 150°C for 60 minutes being each 130% or more.

Description

Technical Field

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

[0002] This method of fixing a component into a gap formed by inserting and fixing one component to another, or into a gap formed 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 fixed 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 above-described fixing method, to prevent the inserted component from falling into 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 sometimes shifts position within the gap or falls out of the gap. Furthermore, because adjustments to the viscosity and filling amount of the liquid adhesive are required, the process is complex and sometimes time-consuming. Moreover, in the above-described method, the adhesive adheres to the outside of the gap of the component, becoming a cause of contamination.

[0004] Therefore, in recent years, research has been conducted on methods for joining insert members and inserted members using adhesive sheets instead of liquid adhesives. Among these methods, research is being conducted on a method in which an expandable adhesive sheet is placed together with the insert member in the gap of the inserted member, so that the adhesive sheet expands and fills the gap to join the insert member and the inserted member.

[0005] For example, Patent Document 1 discloses an adhesive sheet having an adhesive layer (B) directly or in between on one side of an adhesive layer (A). After being placed at 130°C for 1 hour, the expansion rate in the thickness direction of the adhesive layer (A) is above a predetermined value and the expansion rate in the thickness direction of the adhesive layer (B) is below a predetermined value.

[0006] Patent document 2 discloses an adhesive sheet having a pressure-sensitive adhesive layer (B) directly or in between on one side of an intumescent adhesive layer (A), wherein the thickness of the pressure-sensitive adhesive layer (B) is within a specified range and the 180-degree peel adhesion force at room temperature (23°C) is above a specified value.

[0007] Existing technical documents

[0008] Patent documents Patent Document 1: Japanese Patent Application Publication No. 2017-052950 Patent Document 2: Japanese Patent Application Publication No. 2019-182977 Summary of the Invention

[0009] The technical problem that the invention aims to solve In the bonding of insert and inserted components, the adhesive sheet used requires the inserting component to be inserted into the gap between the inserted component and the inserted component before the components are bonded together by thermal expansion. Therefore, to avoid hindering insertion, the adhesive sheet at room temperature before insertion must have low or no initial adhesion. On the other hand, after insertion, the inserting and inserted components cannot be immediately bonded. Therefore, before the adhesive sheet is expanded to bond and fix the components together, it requires high initial adhesion at room temperature to prevent it from shifting from its designated position, allowing for temporary fixation. Furthermore, in the bonding of components that operate at high temperatures, such as automotive motors, high heat resistance is required. Therefore, the adhesive sheet must also exhibit excellent adhesive strength at high temperatures, in addition to room temperature, to firmly bond the inserting and inserted components, and possess heat resistance.

[0010] However, as with the adhesive sheet disclosed in Patent Document 1, when a single layer of thermally expandable adhesive is heated to expand and fill the gaps, there is a technical problem that the greater the expansion rate, the lower the adhesive force of the adhesive layer, and it cannot exhibit sufficient adhesive strength under normal temperature and high temperature conditions.

[0011] Furthermore, as with the adhesive sheet disclosed in Patent Document 2, when a thermoplastic pressure-sensitive adhesive layer (B) is provided on one surface to provide temporary fixation, there is a technical problem that the heat resistance is poor and it cannot exhibit sufficient adhesive strength in high-temperature environments, thus making it unsuitable for joining high-temperature components.

[0012] 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, it can take into account both temporary fixation at room temperature before expansion and ease of insertion when inserting one component into a gap in another component. After expansion, it can fully fill the gap and maintain excellent adhesive strength even at high temperature to firmly join the components together.

[0013] Technical solutions for solving technical problems First, the present invention provides an adhesive sheet having a first side and a second side, wherein the first side is composed of a thermosetting adhesive layer A comprising a thermosetting resin and an expanding agent, and the second side is composed of a thermosetting adhesive layer B comprising a thermosetting resin and an expanding agent and having a different composition from the thermosetting adhesive layer A. The thermosetting adhesive layer B is laminated directly or in layers other than one side of the thermosetting adhesive layer A. The shear bond strength of the first side is higher than that of the second side. After heating at 150°C for 60 minutes, the thickness expansion rates of the thermosetting adhesive layer A and the thermosetting adhesive layer B are both 130% or more.

[0014] Second, the present invention provides an article having a first adhesive and a second adhesive, wherein the second adhesive has a gap, the first adhesive is disposed within the gap of the second adhesive, and an expansion of the adhesive sheet is disposed between the first adhesive and the second adhesive within the gap, wherein one of the first adhesive and the second adhesive is bonded to the expansion of the thermosetting adhesive layer A, and the other is bonded to the expansion of the thermosetting adhesive layer B.

[0015] 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 expansions of the adhesive sheet being disposed within the gap between the first adhesive and the third adhesive, and between the first adhesive and the fourth adhesive, respectively. At least one of the first adhesive, the third adhesive, and the fourth adhesive is bonded to the expansion of the thermosetting adhesive layer A, and the other is bonded to the expansion of the thermosetting adhesive layer B.

[0016] Third, the present invention provides a method for manufacturing an article, comprising the following steps: step [1A], wherein the surface of the thermosetting adhesive layer A side of the adhesive sheet is adhered to the surface of the first adhered object or the surface of the gap formed in the second adhered object; step [2A], wherein the first adhered object is inserted into the gap; and step [3A], wherein the adhesive sheet is heated to cause the thermosetting adhesive layer A and the thermosetting adhesive layer B to expand and solidify, and the first adhered object and the second adhered object are bonded together through the expanded material of the adhesive sheet.

[0017] In addition, the present invention provides a method for manufacturing an article, comprising the following steps: step [1B], wherein the surface of the thermally expandable thermosetting adhesive layer A of the adhesive sheet is adhered to the surface of the first adhered object or to the surface of the gap formed by the third adhered object and the fourth adhered object; step [2B], wherein the first adhered object is inserted into the gap; and step [3B], wherein the adhesive sheet is heated to expand and cure the thermally expandable thermosetting adhesive layer A and the thermally expandable thermosetting adhesive layer B, thereby bonding the first adhered object with the third adhered object and the fourth adhered object through the expanded material of the adhesive sheet.

[0018] Invention Effects The adhesive sheet according to the present invention has a first side and a second side. The first side is composed of a thermosetting adhesive layer A with a specified expansion rate when heated, and the second side is composed of a thermosetting adhesive layer B with a specified expansion rate when heated. By giving the first side and the second side different shear bond strengths, it is possible to balance the temporary fixation of the component at room temperature before expansion and the ease of insertion when inserting one component into the gap of another component. After expansion, it can fully fill the gap and maintain excellent bond strength even in high temperature environments, so that the components are firmly joined together. Attached Figure Description

[0019] Figure 1 This is a schematic cross-sectional view showing an example of the adhesive sheet of the present invention.

[0020] Figure 2 This is a schematic cross-sectional view showing an example of the adhesive sheet of the present invention.

[0021] Figure 3 This is a process diagram illustrating an example of a method for manufacturing the article of the present invention.

[0022] Figure 4 This is a process diagram illustrating an example of a method for manufacturing the article of the present invention.

[0023] Figure 5 This is a schematic diagram illustrating the method for measuring the shear bond strength of an adhesive sheet after heating (expansion). Detailed Implementation

[0024] I. Adhesive sheet The adhesive sheet of the present invention has a first side and a second side. The first side is composed of a thermosetting adhesive layer A containing a thermosetting resin and an expanding agent. The second side is composed of a thermosetting adhesive layer B containing a thermosetting resin and an expanding agent, and having a different composition from the thermosetting adhesive layer A. The thermosetting adhesive layer B is laminated directly or in layers other than one side of the thermosetting adhesive layer A. The shear bond strength of the first side is higher than that of the second side. After heating at 150°C for 60 minutes, the thickness expansion rates of the thermosetting adhesive layer A and the thermosetting adhesive layer B are both 130% or more.

[0025] Figures 1-2 This is a schematic cross-sectional view showing an example of the adhesive sheet of the present invention. Figure 1 (a) and Figure 2 (a) is an example diagram showing the state before heating. Figure 1 (b) and Figure 2 (b) is an example diagram showing the result after heating. For example... Figures 1-2 As shown, the adhesive sheet 10 of the present invention has a thermally expandable thermosetting adhesive layer A constituting the first surface. Figure 1 (1) and Figure 2 (1) The figure reference numeral 1) and the thermally expandable thermosetting adhesive layer B constituting the second surface opposite to the first surface described above. Figure 1 (1) and Figure 2 (1) Reference numeral 2). Thermosetting adhesive layers A and B each contain at least a thermosetting resin and an expanding agent, but thermosetting adhesive layer B has a different composition from thermosetting adhesive layer A.

[0026] In addition, the thermosetting adhesive layer B is laminated directly or in between other layers onto one side of the thermosetting adhesive layer A. Figure 1 The illustrated adhesive sheet 10 represents a direct lamination of thermally expandable thermosetting adhesive layer A and thermally expandable thermosetting adhesive layer B. Figure 2 The illustrated adhesive sheet 10 indicates that an intermediate layer is separated between the thermosetting adhesive layer A and the thermosetting adhesive layer B. Figure 2 The figure in Figure 3) indicates the way other layers are stacked.

[0027] Here, the adhesive sheet 10 of the present invention is characterized in that the shear bond strength of the first surface is higher than that of the second surface. Furthermore, the thermally expandable thermosetting adhesive layers A and B are layers that expand and cure by heating. In the expanded adhesive sheet 10', the thermally expandable thermosetting adhesive layer A (… Figure 1 (2) and Figure 2(2) reference numeral 1') and the above-mentioned thermally expandable thermosetting adhesive layer B ( Figure 1 (2) and Figure 2 In (2) of the attached figure, reference numeral 2') shows that after heating at 150°C for 60 minutes, the expansion rates in the thickness direction of the above-mentioned thermosetting adhesive layer A and the above-mentioned thermosetting adhesive layer B are both above a specified value, and can fill the space through thermal expansion. In addition, the expanded thermosetting adhesive layer A and the expanded thermosetting adhesive layer B also exhibit high adhesive strength in high-temperature environments.

[0028] According to the adhesive sheet of the present invention, in the manufacture of an article in which an insert member is fixed in the gap of an insertable member, a member can be temporarily fixed at room temperature on the first surface formed by the thermosetting adhesive layer A, and the second surface formed by the thermosetting adhesive layer B can prevent the insertion of the insert member from being hindered by the adhesiveness of the adhesive sheet surface when the insert member is inserted into the gap. Furthermore, the thermosetting adhesive layers A and B exhibit an expansion rate of more than a specified value under specific heating conditions. Thus, while filling the gap generated after the insert member is inserted, the expanded thermosetting adhesive layers A and B exhibit curing-based adhesive force. Therefore, the insert member and the insertable member can be firmly bonded together through the expanded adhesive sheet, and high adhesive force can be maintained even at high temperatures through heat curing.

[0029] The adhesive sheet of the present invention can perform the above-mentioned functions regardless of the size of the gap. For example, when using the expanded material of the adhesive sheet to fill and bond narrow gaps, with the first surface of the adhesive sheet simultaneously fixed to the adhered object, the second surface of the adhesive sheet is prone to contact with other components, thus easily causing obstruction of insertion and displacement of the adhesive sheet position. In contrast, in the present invention, the two main surfaces of the first and second surfaces of the adhesive sheet, which are in a relative relationship, have different adhesive properties. Therefore, even in narrow gaps, the second surface of the adhesive sheet will not obstruct the insertion of components, exhibiting good insertion performance. In addition, it is difficult for the adhesive sheet to shift its bonding position. Furthermore, when using the expanded material of the adhesive sheet to fill and bond wide gaps, it is necessary to increase the expansion rate of the thermosetting adhesive layer. If the expansion rate of a single layer of thermosetting adhesive layer becomes too large, the adhesive strength, especially at high temperatures, is prone to decrease. This is presumably because the density within the thermosetting adhesive layer decreases due to expansion, easily leading to high-temperature degradation and reduced heat resistance. In contrast, in this invention, there are two thermosetting adhesive layers A and B with an expansion rate of more than a specified value under specific heating conditions. Each adhesive layer A and B is expanded and cured by heating, so that even wide gaps can be fully filled, and components can be joined together with high adhesive strength in a high-temperature environment, and the joint can be maintained.

[0030] The shear bond strength of the first side of the adhesive sheet of the present invention is greater than that of the second side, thereby enabling temporary fixation on the first side and insertion capability on the second side. Specifically, the difference between the shear bond strength of the first side and the shear bond strength of the second side of the adhesive sheet is preferably 0.01 MPa or more, more preferably 0.1 MPa or more, and even more preferably 0.5 MPa or more. By ensuring that the difference between the shear bond strength of the first side and the second side of the adhesive sheet is within the above range, the first side and the second side can each fully perform the aforementioned functions. This is because it is possible to prevent the function performed on one side from impairing the function performed on the other side. The greater the difference between the shear bond strength of the first side and the shear bond strength of the second side of the adhesive sheet, the better, but there is no particular limitation; for example, it can be 2 MPa or less, or even 1 MPa or less.

[0031] The first surface of the adhesive sheet of the present invention only needs to have a shear bond strength sufficient to provide temporary fixation, and is set to be higher than the shear bond strength of the second surface. The shear bond strength of the first surface of the adhesive sheet is preferably 0.2 MPa or more, more preferably 0.5 MPa or more, and from the viewpoint of providing even higher temporary fixation on the first surface of the adhesive sheet, it is more preferably 1.0 MPa or more. Furthermore, the higher the shear bond strength of the first surface of the adhesive sheet, the better; there is no particular upper limit to the shear bond strength, but it can be, for example, 2 MPa or 1 MPa. The shear bond strength of the first surface of the adhesive sheet mainly depends on the shear bond strength of the thermally expandable thermosetting adhesive layer A constituting the first surface, and can be appropriately adjusted according to the layer composition of the adhesive sheet, etc.

[0032] On the other hand, the second side of the adhesive sheet only needs to have a shear bond strength sufficient for insertion, and is set to be lower than the shear bond strength of the first side. The shear bond strength of the second side of the adhesive sheet 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 side of the adhesive sheet 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 thermosetting adhesive layer B, the less the initial adhesion disappears, and the better the insertion performance when inserting the insertion member into the gap. Therefore, the lower limit is preferably 0 MPa, and can also be 0.01 MPa or more. The shear bond strength of the second side of the adhesive sheet is mainly due to the shear bond strength of the thermosetting adhesive layer B constituting the second side, and can be adjusted according to the layer composition of the adhesive sheet, etc.

[0033] The shear adhesive 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, fix one of the first and second sides of the cut adhesive sheet (the side not to be tested) with a strong adhesive. Align the other side of the adhesive sheet (the side to be tested) with the surface of the other aluminum plate B. Clamp the adhesive sheet between the two aluminum plates A and B and press it under a load of 0.5MPa at 23°C for 10 seconds to obtain the test piece. Next, place the test piece at 23°C for 5 minutes, then 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 surface (the surface to be measured) of the adhesive sheet on the B side of the aluminum.

[0034] 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.

[0035] The first and second surfaces of the adhesive sheet refer to one and the other outermost surfaces of the adhesive sheet excluding the release liner. Furthermore, unless otherwise specified, when referring to "adhesive sheet," "thermally expanding thermosetting adhesive layer A," or "thermally expanding thermosetting adhesive layer B," it refers to the "adhesive sheet," "thermally expanding thermosetting adhesive layer A," or "thermally expanding thermosetting adhesive layer B" before expansion. Moreover, "expansion of the adhesive sheet," "expansion of the thermosetting thermosetting adhesive layer A," and "expansion of the thermosetting thermosetting adhesive layer B" respectively refer to "expanded adhesive sheet," "expanded thermosetting thermosetting adhesive layer A," and "expanded thermosetting thermosetting adhesive layer B." "After expansion" refers to the expansion and curing of the thermosetting thermosetting adhesive layer; unless otherwise specified, it refers to "after heating at 150°C for 60 minutes."

[0036] (1) Thermal expansion thermosetting adhesive layer A The thermosetting adhesive layer A in this invention is a layer containing at least a thermosetting resin and an expanding agent. The thermosetting adhesive layer A constitutes the first surface of the adhesive sheet of this invention, excluding the release liner.

[0037] The shear bond strength of the thermosetting adhesive layer A is higher than that of the thermosetting adhesive layer B (described later). Due to the initial adhesiveness of the thermosetting adhesive layer A, temporary fixation can be achieved while the adhesive sheet is heated to expand and bonded to the inserted member, ensuring that the first surface of the adhesive sheet does not deviate from a predetermined position on the member. Specifically, the shear bond strength of the thermosetting adhesive layer A is preferably 0.2 MPa or higher, more preferably 0.5 MPa or higher, and more preferably 1.0 MPa or higher from the viewpoint of obtaining an adhesive sheet with even higher temporary fixation. Furthermore, the higher the shear bond strength of the thermosetting adhesive layer A, the better; for example, an upper limit of 2 MPa or 1 MPa can be set. The shear bond strength of the thermosetting adhesive layer A can be adjusted, for example, by the combination of the resin components, inorganic fillers, tackifiers and other additives contained in the thermosetting adhesive layer A, which will be described later.

[0038] The shear bond strength of the thermosetting adhesive layer A can be determined according to the tensile shear test described in JIS Z 1541 by the following method. First, the thermosetting adhesive layer A, identical to the thermosetting adhesive layer A in the adhesive sheet, is molded into a sheet. The molded part is cut into 10mm × 10mm pieces. Two degreased, smooth aluminum plates (15mm wide × 70mm long × 0.5mm thick) are clamped together and pressed under a load of 0.5MPa at 23°C for 10 seconds to obtain the test piece. After placing the test piece at 23°C for 5 minutes, the ends of the two aluminum plates are clamped separately, 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.

[0039] Furthermore, the thermosetting adhesive layer A, upon heating, expands and undergoes a thermosetting reaction, exhibiting adhesive strength capable of withstanding high-temperature environments. After heating at 150°C for 60 minutes, the thickness-direction expansion rate of the aforementioned thermosetting adhesive layer A is 130% or more, sufficient to fill the voids in the inserted component together with the expansion of the thermosetting adhesive layer B (described later). Preferably, the expansion rate is 150% or more, more preferably 175% or more, and particularly preferably 200% or more. However, if the expansion rate of the thermosetting adhesive layer A after expansion is too large, the layer density becomes sparse, easily leading to thermal degradation under high-temperature conditions, and sometimes failing to exhibit and maintain sufficient adhesive strength. Therefore, the expansion rate in the thickness direction of the thermosetting adhesive layer A after heating at 150°C for 60 minutes is preferably 1000% or less, more preferably 500% or less, even more preferably 450% or less, more preferably 400% or less, and particularly preferably 300% or less. By ensuring that the expansion rate of the thermosetting adhesive layer A after heating at 150°C for 60 minutes is within the above-mentioned range, the expansion of the thermosetting adhesive layer A can fully fill the gaps of the inserted member, and a high adhesive force can be maintained on the adherend, i.e., the inserted member or the inserted member, to firmly bond the inserted member and the inserted member.

[0040] The thickness-direction expansion rate (%) of the thermosetting adhesive layer A (the expanded material of thermosetting adhesive layer A) after heating at 150°C for 60 minutes is a value calculated based on the following method and mathematical formula. First, the thickness of the thermosetting adhesive layer A of the adhesive sheet before heating is measured at 23°C. Next, after heating the adhesive sheet at 150°C for 60 minutes, the adhesive sheet is removed and placed at 23°C, and the thickness of the thermosetting adhesive layer A of the adhesive sheet after heating is immediately measured. Based on the above measurement results and the following mathematical formula, the expansion rate is calculated.

[0041] The expansion rate (%) of the thermal expansion thermosetting adhesive layer A after heating = [thickness of thermal expansion thermosetting adhesive layer A after heating / thickness of thermal expansion thermosetting adhesive layer A before heating] × 100 (%) It should be noted that, instead of the adhesive sheet, a thermosetting adhesive layer A with the same thermal expansion thermosetting adhesive layer A as in the adhesive sheet can be formed on the release liner and used as a test sample. Based on the thickness of the thermosetting adhesive layer A before and after heating the test sample at 150°C for 60 minutes, the expansion rate can be calculated based on the above mathematical formula.

[0042] The shear bond strength of the expanded thermosetting adhesive layer A is preferably 3 MPa or more at room temperature (23°C), more preferably 6 MPa or more, and even more preferably 9 MPa or more. By ensuring that the shear bond strength of the expanded thermosetting adhesive layer A is within the above range, the adhesion retention performance between the inserted member and the inserted member is improved. Furthermore, the higher the shear bond strength of the expanded thermosetting adhesive layer A, the better; however, there is no particular upper limit to the shear bond strength after expansion, for example, it can be 30 MPa or 15 MPa.

[0043] The shear bond strength of the expanded thermosetting adhesive layer A can be determined according to the tensile shear test described in JIS Z 1541. The test piece is heated at 150°C for 60 minutes and then subjected to a tensile test. Otherwise, the method for determining the shear bond strength of the unexpanded thermosetting adhesive layer A is the same as described above.

[0044] To achieve even better bond strength, the thickness of the thermally expandable thermosetting adhesive layer A is preferably 1 mm. μ m or more, preferably 10 μ m~250 μ The range of m is further preferably 15. μ m~150 μ The range of m is particularly preferred to be 20. μ m~100 μ The range is m. Furthermore, the thickness of the expanded, thermosetting adhesive layer A is preferably 20 mm in order to achieve even better adhesive strength. μ m~2500 μ The range of m is more preferably 30. μ m~1500 μ The range of m. The thermally expandable thermosetting adhesive layer A, after expansion, preferably has a porous structure.

[0045] The thermally expandable thermosetting adhesive layer A preferably occupies 10% or more of the total thickness of the adhesive sheet, more preferably 30% or more. This is because, by setting it to the above range, it is easy to fill the gap while fixing the inserted member into the gap of the inserted member. It should be noted that, in the case where the adhesive sheet has a release liner, the total thickness of the adhesive sheet does not include the thickness of the release liner.

[0046] The expanded thermosetting adhesive layer A has a glass transition temperature of 80°C or higher, exhibiting excellent adhesive strength even when exposed to high-temperature environments. It is particularly advantageous for firmly maintaining the 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 A is preferably 100°C or higher and 300°C or lower, more preferably 120°C or higher and 280°C or lower, and even more preferably 150°C or higher and 250°C or lower.

[0047] The glass transition temperature of the expanded thermosetting adhesive layer A is determined by using a dynamic viscoelasticity measuring apparatus (manufactured by Rheometrics, trade name: RSA-II). The apparatus clamps the test piece using its measuring section (clamp), measures the storage modulus (E') and loss modulus (E'') at a frequency of 1 Hz, and calculates the loss tangent (tanδ) obtained by dividing the loss modulus (E') by the storage modulus (E'). It should be noted that the test piece used in the above measurement can be a test piece obtained by punching the expanded thermosetting adhesive layer A (heated at 150°C for 60 minutes) into the shape of JIS K 7127 test piece type 5 using a dumbbell-shaped cutter.

[0048] The aforementioned thermosetting adhesive layer A preferably has a curing rate of 80% or more after expansion. 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, it is more preferable to have a curing rate of 90% or more after expansion, and even more preferably to have a curing rate of 99% or more.

[0049] It should be noted that the curing rate of the expanded thermosetting adhesive layer A is expressed by the gel fraction, which refers to the mass of the dried thermosetting adhesive layer A remaining in the solvent after immersion in a toluene solution adjusted to 23°C for 24 hours after heating the thermosetting adhesive layer A at 150°C for 60 minutes. This mass is calculated based on the following mathematical formula.

[0050] Gel fraction (mass%) = {(mass of the expanded thermosetting adhesive layer that does not dissolve in toluene and remains) / (mass of the expanded thermosetting adhesive layer before toluene impregnation)} × 100 The thermosetting adhesive layer A is a layer containing at least a thermosetting resin and an expanding agent. In other words, the thermosetting adhesive layer A is a layer formed from a thermosetting adhesive composition a containing at least a thermosetting resin and an expanding agent. The thermosetting adhesive layer A can be formed, for example, by applying the above-mentioned thermosetting adhesive composition a to a release liner or the like and allowing it to dry.

[0051] It should be noted that "in all resin components of the thermally expanding thermosetting adhesive layer A" refers to "all resin components of the thermally expanding thermosetting adhesive composition a (which can form the thermally expanding thermosetting adhesive layer A)". Resin components refer to the resin components that constitute the adhesive composition excluding the expanding agent.

[0052] (Thermosetting resin) The thermosetting adhesive layer A, which is heat-expandable and thermosetting, contains at least a thermosetting resin as a resin component. As the thermosetting resin contained in the thermosetting adhesive layer A, 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 resin and / or acrylic resin are preferred as thermosetting resins in terms of imparting good adhesion to the adhered objects upon thermal expansion, and epoxy resin is further preferred in terms of ensuring good heat curing properties and high heat resistance.

[0053] Specifically, the epoxy resins used can include bisphenol type epoxy resins such as bisphenol A type epoxy resin and bisphenol F type epoxy resin, aliphatic epoxy 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, and 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxa- Epoxy resins include chemically modified epoxy resins, phenolic varnish-type epoxy resins, cresol phenolic varnish-type epoxy resins, triphenylmethane-type epoxy resins, tetraphenylethane-type epoxy resins, phenol aralkyl-type epoxy resins, naphthol phenolic varnish-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, and biphenyl-modified phenolic varnish-type epoxy resins, etc. Epoxy resins can be used alone or in combination with two or more types.

[0054] The thermosetting resin contained in the thermally expandable thermosetting adhesive layer A preferably has a total epoxy equivalent of 2000 g / eq. or less. This is preferred because it can increase the glass transition temperature of the expanded thermally expandable thermosetting adhesive layer A 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, and 150 g / eq. or more and 500 g / eq. or less.

[0055] In the thermosetting adhesive layer A, the thermosetting resin is preferably an epoxy resin with an epoxy equivalent of 500 g / eq. or less, which is present in 30% to 90% by mass of the total resin composition of the thermosetting adhesive layer A. This can increase the glass transition temperature of the expanded thermosetting adhesive layer A and suppress the decrease in adhesive strength at high temperatures. The epoxy equivalent of the epoxy resin included in the thermosetting adhesive layer A is preferably 10 g / eq. or more and 450 g / eq. or less, 20 g / eq. or more and 400 g / eq. or less, or 50 g / eq. or more and 300 g / eq. or less. Furthermore, the content of epoxy resin with an epoxy equivalent within the above range is preferably in the range of 35% to 85% by mass, 40% to 80% by mass, or 50% to 70% by mass of the total resin composition of the thermosetting adhesive layer A. Within the above range, the content of epoxy resin with epoxy equivalent is the total amount when the above range includes two or more epoxy resins with epoxy equivalent.

[0056] It should be noted that the "epoxy equivalent" in this application 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 Resin (2001) (perchloric acid-tetraethylammonium bromide method), etc.

[0057] Thermosetting adhesive layer A preferably contains one or more solid thermosetting resins (hereinafter referred to as solid resins; the same applies to thermosetting adhesive layer B). In this specification, "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. Furthermore, the content of the solid resin in the total resin composition of thermosetting adhesive layer A is preferably 10% by mass or higher, more preferably 20% by mass or higher, 30% by mass or higher, 40% by mass or higher, and 50% by mass or higher. Furthermore, the content of solid resin in the total resin composition of the thermosetting adhesive layer A is preferably 95% by mass or less, more preferably 90% by mass or less, 85% by mass or less, 80% by mass or less, or 70% by mass or less. More specifically, the content of solid resin is preferably 10% by mass or more, more preferably 20% by mass or more and 95% by mass or less, and more preferably 40% by mass or more and 70% by mass or less. This is because it imparts initial adhesion (adhesiveness) to the thermosetting adhesive layer A and easily maintains its sheet-like shape at room temperature, improving workability. When containing two or more solid resins, the content of solid resin is the total amount of the two or more solid resins.

[0058] 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. A single solid resin may be used, or two or more may be used.

[0059] Furthermore, the thermosetting adhesive layer A preferably contains a thermosetting resin that is liquid at 25°C (hereinafter referred to as liquid resin. The same applies to the thermosetting adhesive layer B). This is because it can improve the shear bond strength of the thermosetting adhesive layer A and exhibit good temporary fixation. The viscosity of the liquid resin contained in the thermosetting adhesive layer A at 25°C is preferably 3,000,000 mPa·sec or less, more preferably 10,000,000 mPa·sec or more and 2,000,000 mPa·sec or less, and more preferably 1,000,000,000 mPa·sec or more and 1,000,000,000 mPa·sec or less. In addition, the content of liquid resin in the thermosetting adhesive layer A is preferably 10% by mass or more of the total resin component of the thermosetting adhesive layer A, more preferably 15% by mass or more, more preferably 20% by mass or more, and more preferably 30% by mass or more. Furthermore, the content of the aforementioned liquid resin in the total resin composition of the thermosetting adhesive layer A is preferably 70% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less. More specifically, the content of the liquid resin in the thermosetting adhesive layer A can be 10% by mass or more, 15% by mass or more and 70% by mass or less, 20% by mass or more and 60% by mass or less, or 30% by mass or more and 50% by mass or less. By including the aforementioned liquid resin with the desired viscosity in the thermosetting adhesive layer A at a desired content, the initial adhesion (bonding) of the thermosetting adhesive layer can be appropriately imparted, and an adhesive sheet with higher temporary fixation can be obtained. When two or more liquid resins are included, the content of the liquid resin is the total amount of the two or more liquid resins.

[0060] The liquid resin contained in the thermosetting adhesive layer A can be appropriately combined using the aforementioned viscosity range and content range. As a preferred example, the thermosetting adhesive layer A preferably contains at least 20% by mass of a liquid resin with a viscosity of 3 million mPa·sec. or less at 25°C. As another preferred example, the thermosetting adhesive layer A preferably contains at least 12% by mass and at least 70% by mass of the aforementioned liquid resin with a viscosity of 10 mPa·sec. or more and at least 2 million mPa·sec. Furthermore, as yet another preferred example, the thermosetting adhesive layer A preferably contains at least 15% by mass and at least 50% by mass of the aforementioned liquid resin with a viscosity of 1000 mPa·sec. or more and at least 1 million mPa·sec. By including the desired viscosity and content of the liquid resin in the thermosetting adhesive layer A, the desired shear bond strength can be adjusted, resulting in good initial adhesion.

[0061] 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, aliphatic epoxy resins, trimethylolpropane type epoxy resins, alicyclic epoxy resins, 1,6-dihydroxynaphthalene type epoxy resins, tert-butylcatechol type epoxy resins, 4,4'-diaminodiphenylmethane type epoxy resins, p- or m-aminophenol type epoxy resins, trimethylolpropane type epoxy resins, 1,6-hexanediol type epoxy resins, 1,4-butanediol type epoxy resins, and aliphatic chain modified epoxy resins. A single liquid resin may be used, or two or more may be used.

[0062] In the thermosetting adhesive layer A, the mixing ratio of the solid resin to the liquid resin (solid:liquid) is only required to achieve a shear bond strength within the desired range for the thermosetting adhesive layer A. For example, by mass ratio, it is preferably in the range of 95:5 to 40:60, preferably in the range of 90:10 to 50:50, and preferably in the range of 80:20 to 60:40. By ensuring that the mixing ratio of the solid resin to the liquid resin in the thermosetting adhesive layer A is within the above-mentioned range, the desired shear bond strength can be achieved, resulting in good initial adhesion.

[0063] The thermosetting adhesive layer A, which is thermally expandable and thermosetting, uses a thermosetting resin with a weight-average molecular weight of 100 or more and 20,000 or less as the thermosetting resin. This is preferred from the viewpoint of being able to appropriately impart initial adhesion (bonding) to the thermosetting adhesive layer and obtain an adhesive sheet with higher temporary fixation. The weight-average molecular weight of the thermosetting resin is preferably 150 or more and 10,000 or less, more preferably 200 or more and 4,000 or less. The weight-average molecular weight of the thermosetting resin is a conversion value to standard polystyrene.

[0064] The total content of the aforementioned thermosetting resin, in 100% by mass of all resin components of the thermosetting adhesive layer A, is preferably contained in the range of 10% to 99% by mass, more preferably in the range of 40% to 80% by mass, and even more preferably in the range of 50% to 70% by mass. By ensuring that the content of thermosetting resin in the thermosetting adhesive layer A is within the above range, the initial adhesion (bonding property) of the thermosetting adhesive layer can be appropriately imparted, resulting in an adhesive sheet with higher temporary fixation, which easily maintains its sheet shape at room temperature, thus improving workability. The thermosetting adhesive layer A is preferably a layer whose main component includes thermosetting resin, and more preferably a layer whose main component includes epoxy resin.

[0065] (Expanding agent) As the expanding agent included in the thermosetting adhesive layer A, it is preferable to use an expanding agent that can form a porous structure within the expanded thermosetting adhesive layer A. Examples of such expanding agents include inorganic compounds such as ammonium carbonate, ammonium bicarbonate, ammonium nitrite, and ammonium borohydride, 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.

[0066] In addition, as the aforementioned expanding agent, for example, expandable capsules obtained by microencapsulating hydrocarbon solvents can be used. Expanding agents can be used alone or in combination of two or more.

[0067] As the aforementioned expanding agent, the use of expanding capsules obtained by microencapsulating hydrocarbon solvents is more preferable, for example, in preventing the deterioration of the thermally expanding thermosetting adhesive layer A caused by the influence of heat, etc.

[0068] 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 A, since it can fully expand the adhesive sheet of the present invention.

[0069] 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.). Preferably, the expandable capsules used have a volume expansion rate (volume expansion ratio) that is 8 to 60 times greater than the volume of the capsule before expansion.

[0070] The content of the aforementioned expanding agent, preferably the content of the aforementioned thermally expandable capsule, is preferably in the range of 0.3 parts by weight to 30 parts by weight, more preferably in the range of 0.5 parts by weight to 25 parts by weight, and even more preferably in the range of 1 part by weight to 20 parts by weight, relative to 100 parts by weight of the total resin component of the aforementioned thermally expandable thermosetting adhesive layer A. By ensuring that the content of the expanding agent is within the aforementioned range, the gaps in the inserted member can be sufficiently filled, and a high adhesive force can be maintained on the adhered object, i.e., the inserted member or the inserted member, thereby firmly bonding the inserted member and the inserted member together.

[0071] (Curing agent) The thermosetting adhesive layer A preferably contains a curing agent capable of reacting with the thermosetting resin. This is because, when the thermosetting adhesive layer A is heated, the thermosetting resin fully cures, exhibiting high adhesive strength. The curing agent 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.

[0072] The curing agent described above can be appropriately selected from compounds corresponding to the type of thermosetting resin, particularly the type of functional groups possessed by the thermosetting resin. For example, when using epoxy resin as the thermosetting resin, it is preferable to use a curing agent having functional groups capable of reacting with the epoxy group. Specifically, examples of curing agents include amine compounds, amide compounds, acid anhydride compounds, and phenolic compounds.

[0073] As amine compounds, for example, 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 and polyamide resins synthesized from dimers of linolenic acid and 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] In the case where the aforementioned curing agent, for example, uses epoxy resin as the thermosetting resin, the ratio of the equivalent amount of functional groups in the curing agent capable of reacting 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, thereby improving the heat resistance of the adhesive sheet.

[0078] As the curing agent mentioned above, a powder curing agent is preferred. Compared with a liquid curing agent, the above-mentioned powder curing agent suppresses the thermal curing reaction at low temperatures, thus further improving the storage stability of the thermally expandable thermosetting adhesive layer A at room temperature.

[0079] The content of the curing agent can be appropriately set in a manner that is within the range of the curing rate after the thermal expansion of the above-mentioned thermosetting adhesive layer A.

[0080] (Curing accelerator) The thermosetting adhesive layer A and the thermosetting adhesive composition a constituting thereof may also contain a curing accelerator. The curing accelerator is preferably contained before the thermosetting adhesive layer A is thermosetting, or before it is formed into a sheet-like thermosetting adhesive layer A. Phosphorus compounds, amine compounds, imidazole derivatives, etc., can be used as the curing accelerator. The amount of 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 A.

[0081] As a curing accelerator, a powder curing accelerator is preferred. Compared with a liquid curing accelerator, the above-mentioned powder curing accelerator inhibits the thermosetting reaction at low temperatures, thus further improving the room temperature storage stability of the thermally expandable thermosetting adhesive layer A.

[0082] (Thermoplastic resin) The thermoplastic adhesive layer A and the thermoplastic adhesive composition a constituting therein may contain thermoplastic resin even when used in environments with large temperature variations after expansion, without compromising the fixation of the joint.

[0083] Examples of thermoplastic resins that can be used include urethane resins such as thermoplastic polyurethane (TPU); phenoxy resins such as polyhydroxy polyethers synthesized from bisphenols and epichlorohydrin; polycarbonate (PC); vinyl chloride resins such as polyvinyl chloride (PVC) and vinyl chloride-vinyl acetate copolymer; 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. Polystyrene resins such as polystyrene (PS), 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 A 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 thermosetting adhesive layer A can exhibit stronger adhesive strength. Examples of reactive groups that react with the thermosetting resin include epoxy, hydroxyl, carboxyl, amino, and isocyanate groups. Examples of thermoplastic resins having such reactive groups include thermoplastic polyurethane (TPU), polyhydroxy polyether (phenoxy resin), and acrylic resin.

[0085] Based on the above reasons, the thermoplastic resin can be used in the range of 1 to 100 parts by weight relative to 100 parts by weight of the thermosetting resin in the thermally expanding thermosetting adhesive layer A. Specifically, it is preferable to use it in the range of 10 to 150 parts by weight relative to 100 parts by weight of the thermosetting resin, and from the viewpoint of exhibiting strong adhesive force, it is more preferable to use it in the range of 30 to 100 parts by weight.

[0086] (Any ingredient) In addition to the above-mentioned components, the thermally expandable thermosetting adhesive layer A 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.

[0087] (2) Thermal expansion thermosetting adhesive layer B The thermosetting adhesive layer B of this invention contains at least a thermosetting resin and an expanding agent, but its composition differs from that of the thermosetting adhesive layer A. The thermosetting adhesive layer B is a layer constituting the second side of the adhesive sheet of this invention, excluding the release liner.

[0088] The shear bond strength of the thermosetting adhesive layer B is lower than that of the thermosetting adhesive layer A. Preferably, it has low initial adhesion (bondability) or no initial adhesion. When inserting the insert member into the gap of the inserted member, it prevents the second side of the adhesive sheet from adhering to the adhered object, thus preventing misalignment of the adhesive sheet or adhesion to a position different from the specified position, and improves insertion performance.

[0089] The thermosetting adhesive layer B only needs to have a lower shear bond strength at room temperature than the thermosetting adhesive layer A. Specifically, the shear bond strength of the thermosetting adhesive layer B 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 side of the adhesive sheet of the present invention being adhered to a position different from the predetermined position, and improving the insertability when inserting the inserting member into the gap, it is more preferably 0.1 MPa or less. In addition, the lower the shear bond strength of the thermosetting adhesive layer B, the more likely the initial adhesion will disappear, and the more the insertability when inserting the inserting member into the gap will be improved. Therefore, the lower limit value is preferably 0 MPa, but it can also be 0.01 MPa or more. The shear bond strength of the thermosetting adhesive layer B can be adjusted, for example, by the combination of the resin components, inorganic fillers, slip agents, and other additives contained in the thermosetting adhesive layer B, as described later.

[0090] The shear bond strength of the thermosetting adhesive layer B can be measured using the same method as the method for measuring the shear bond strength of the thermosetting adhesive layer A described above.

[0091] Furthermore, the thermosetting adhesive layer B expands upon heating, undergoing a thermosetting reaction, and exhibits high adhesive strength even at high temperatures. After heating at 150°C for 60 minutes, the thickness-direction expansion rate of the thermosetting adhesive layer B is 130% or more, sufficient to fill the voids in the inserted member together with the expansion of the thermosetting adhesive layer A. Preferably, the expansion rate of the thermosetting adhesive layer B is 150% or more, more preferably 175% or more, and particularly preferably 200% or more. However, if the expansion rate of the thermosetting adhesive layer B is too large, the layer density becomes loose, and therefore, especially at high temperatures, it may deteriorate and fail to exhibit sufficient adhesive strength. Therefore, the expansion rate in the thickness direction of the thermosetting adhesive layer B after heating at 150°C for 60 minutes is preferably 1000% or less, more preferably 500% or less, more preferably 450% or less, further preferably 400% or less, and particularly preferably 300% or less. By ensuring that the expansion rate of the thermosetting adhesive layer B after heating at 150°C for 60 minutes is within the above-mentioned range, the expansion of the thermosetting adhesive layer B can fully fill the gaps of the inserted member, and even under high-temperature conditions, it can maintain high adhesive force to the adhered object, i.e., the inserted member or the inserted member, and firmly bond the inserted member and the inserted member together.

[0092] The thickness expansion rate (%) of the thermosetting adhesive layer B after heating at 150°C for 60 minutes can be determined by the same method as the thickness expansion rate (%) of the thermosetting adhesive layer A before and after heating, and is calculated based on the following mathematical formula.

[0093] The expansion rate (%) of the thermally expandable thermosetting adhesive layer B after heating = [thickness of the thermally expandable thermosetting adhesive layer B after heating / thickness of the expandable adhesive layer B before heating] × 100 (%) Furthermore, the shear bond strength of the expanded thermosetting adhesive layer B is preferably 3 MPa or more at room temperature (23°C), more preferably 6 MPa or more, and even more preferably 9 MPa or more. By ensuring that the shear bond strength of the expanded thermosetting adhesive layer B is within the above range, the adhesion retention function between the inserted member and the inserted member is improved. It should be noted that the higher the shear bond strength of the expanded thermosetting adhesive layer B, the better; for example, it can be set to 30 MPa or less, or even 15 MPa.

[0094] The shear bond strength of the expanded thermosetting adhesive layer B can be determined by the same method as the method for determining the shear bond strength of the expanded thermosetting adhesive layer A described above.

[0095] To achieve even better bond strength, the thickness of the thermally expandable thermosetting adhesive layer B is preferably 1 mm. μ m or more, preferably 10 μ m~250 μ The range of m is further preferably 20. μ m~200 μ The range of m is particularly preferred to be 40. μ m~150 μ The range of m.

[0096] To achieve even better bond strength, the thickness of the expanded thermally expandable thermosetting adhesive layer B is preferably 50 mm. μ m~2500 μ The range of m is more preferably 60. μ m~1500 μ The range is m. Furthermore, the expanded, thermally expandable, thermosetting adhesive layer B preferably has a porous structure.

[0097] The thickness of the thermosetting adhesive layer B, which accounts for 15% or more of the total thickness of the adhesive sheet, is preferably 35% or more. This is because, by setting it to the above range, it is easy to fill the gap while fixing the inserted member into the gap of the inserted member. It should be noted that, in the case where the adhesive sheet has a release liner, the total thickness of the adhesive sheet does not include the thickness of the release liner.

[0098] The glass transition temperature of the expanded thermosetting adhesive layer B is preferably 80°C or higher. This is because the expanded thermosetting adhesive layer B can maintain excellent adhesive strength even when exposed to high-temperature environments, especially in firmly maintaining the bond between the insert and the inserted component for applications where high temperatures are easily reached. More specifically, the glass transition temperature of the expanded thermosetting adhesive layer B is preferably 100°C or higher and 300°C or lower, more preferably 120°C or higher and 280°C or lower, and even more preferably 150°C or higher and 250°C or lower.

[0099] The glass transition temperature of the expanded thermally expandable thermosetting adhesive layer B was determined by the same method as the method for determining the glass transition temperature of the expanded thermally expandable thermosetting adhesive layer A.

[0100] The aforementioned thermosetting adhesive layer B with thermal expansion is preferably configured to have a curing rate of 80% or higher after expansion. 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, the curing rate after expansion is more preferably set to 90% or higher, and even more preferably 99% or higher.

[0101] It should be noted that the curing rate of the expanded thermosetting adhesive layer B refers to the value measured and calculated using the same method as the expanded thermosetting adhesive layer A, expressed as the gel fraction.

[0102] The thermosetting adhesive layer B is a layer containing at least a thermosetting resin and an expanding agent. In other words, the thermosetting adhesive layer B is a layer formed from a thermosetting adhesive composition b containing at least a thermosetting resin and an expanding agent. The thermosetting adhesive layer B can be formed by applying the above-mentioned thermosetting adhesive composition b to a release liner or the like and allowing it to dry.

[0103] It should be noted that the term "in all resin components of the thermally expandable thermosetting adhesive layer B" can mean "in all resin components of the thermally expandable thermosetting adhesive composition b that forms the thermally expandable thermosetting adhesive layer B".

[0104] (Thermosetting resin) The thermosetting adhesive layer B contains at least a thermosetting resin as a resin component. As the thermosetting resin contained in the thermosetting adhesive layer B, 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 resin and / or acrylic resin are preferred as thermosetting resins in terms of imparting good adhesion to the adhered surfaces during heat curing, and epoxy resin is more preferred in terms of ensuring good heat curing properties and high heat resistance.

[0105] Specifically, the epoxy resin exemplified in the above-mentioned "thermally expanding thermosetting adhesive layer A" project can be used as the epoxy resin mentioned above.

[0106] The total epoxy equivalent of the thermosetting resin contained in the thermally expandable thermosetting adhesive layer B is preferably 2000 g / eq. or less. This increases the glass transition temperature of the expanded thermally expandable thermosetting adhesive layer and suppresses the decrease in adhesive strength at high temperatures, thus it is preferred. 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, and 150 g / eq. or more and 500 g / eq. or less.

[0107] As the thermosetting resin included in the thermosetting adhesive layer B, it is preferable that the total resin composition of the thermosetting adhesive layer B contains epoxy resin with an epoxy equivalent of 500 g / eq. or less in the range of 30% to 90% by mass. By including epoxy resin with a high epoxy equivalent in the above-mentioned range in a desired amount, the glass transition temperature of the thermosetting adhesive layer after expansion can be increased, and the decrease in adhesive strength at high temperatures can be suppressed, which is therefore preferred. The epoxy equivalent is preferably 20 g / eq. or more and 450 g / eq. or less, 50 g / eq. or more and 400 g / eq. or less, and 100 g / eq. or more and 300 g / eq. or less. Furthermore, the content of epoxy resin having epoxy equivalent within the above-mentioned range is preferably in the range of 35% by mass or more and 85% by mass or less, 40% by mass or more and 80% by mass or less, and 50% by mass or more and 70% by mass or less. The content of epoxy resin having epoxy equivalent within the above-mentioned range refers to the total amount of two or more epoxy resins having epoxy equivalent within the above-mentioned range.

[0108] The thermosetting adhesive layer B preferably contains a solid resin as a thermosetting resin. The softening point of the solid resin contained in the thermosetting adhesive layer B is preferably 5°C or higher and 150°C or lower, more preferably 50°C or higher and 100°C or lower. Furthermore, the content of the solid resin in the thermosetting adhesive layer B is preferably 30% by mass or higher, more preferably 50% by mass or higher, 60% by mass or higher, 70% by mass or higher, 80% by mass or higher, 85% by mass or higher, or 90% by mass or higher, in the total resin composition of the thermosetting adhesive layer B. Moreover, the above-mentioned content is preferably 99% by mass or lower, more preferably 97% by mass or 95% by mass, in the total resin composition of the thermosetting adhesive layer B. More specifically, the content of the solid resin is preferably 30% by mass or higher, preferably 50% by mass or higher and 99% by mass or lower, more preferably 70% by mass or higher and 95% by mass or lower. This is because it can reduce the initial adhesion (bonding) of the thermosetting adhesive layer B, and when the inserting member is inserted into the gap of the inserted member, it can prevent the adhesive sheet from shifting its bonding position or being pasted in a position different from the specified position, and improve the insertion performance.

[0109] Specifically, the solid resins exemplified in the above item "(1) Thermally expandable thermosetting adhesive layer A" can be cited as examples of solid resins. A single solid resin may be used alone, or two or more may be used. In the case of two or more solid resins, the content of the solid resin is the total amount of the two or more solid resins.

[0110] Furthermore, the thermosetting adhesive layer B may or may not be used with a thermosetting resin (hereinafter referred to as liquid resin) that is liquid at 25°C. The viscosity of the liquid thermosetting resin at 25°C is preferably 3,000,000 mPa·sec or less, more preferably 1,000 mPa·sec or more and 2,000,000 mPa·sec or less, and more preferably 10,000 mPa·sec or more and 1,500,000 mPa·sec or less. When the thermosetting adhesive layer B contains liquid resin, the content of the liquid resin in the total resin composition of the thermosetting adhesive layer B is preferably 40% by mass or less, more preferably 30% by mass or less, more preferably 20% by mass or less, and more preferably 10% by mass or less. Additionally, the content of the liquid resin may be 0% by mass, may exceed 0% by mass, may contain 1% or more by mass, may contain 3% or more by mass, or may contain 5% or more by mass. More specifically, the aforementioned 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 including the aforementioned liquid resin with the desired viscosity in the thermosetting adhesive layer B at a desired content, the initial adhesive force of the thermosetting adhesive layer B can be reduced. When the insert member is inserted into the gap of the inserted member, it is possible to prevent the adhesive sheet from shifting its bonding position or being pasted at a position different from the predetermined position, and the insertionability can be improved. In addition, the flexibility of the thermosetting adhesive layer B before expansion and its fluidity during heating can be made appropriate, and the operability of the adhesive sheet of the present invention and the expansion rate of the adhesive sheet caused by heating can be appropriate.

[0111] When the thermosetting adhesive layer B contains a liquid resin, the liquid resin can be appropriately combined using the aforementioned viscosity range and content range. As a preferred example, the thermosetting adhesive layer B preferably contains 20% by mass or less of a liquid resin with a viscosity of 3 million mPa·sec or less at 25°C. As another preferred example, the thermosetting adhesive layer B preferably contains 1% to 15% by mass of the aforementioned liquid resin with a viscosity in the range of 1000 mPa·sec to 2 million mPa·sec. Furthermore, as another preferred example, the thermosetting adhesive layer B preferably contains, for example, 3% to 10% by mass of the aforementioned 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 between the thermosetting adhesive layer B and the second surface of the adhesive sheet formed from the thermosetting adhesive layer B can be sufficiently reduced, and the insertion properties are improved.

[0112] Specifically, examples of such liquid resins include the liquid resin exemplified in the item “(1) Thermo-expandable thermosetting adhesive layer A” above. One type of liquid resin may be used alone, or two or more types may be used. In cases where two or more liquid resins are included, the liquid resin content refers to the total amount of the two or more liquid resins.

[0113] In the thermosetting adhesive layer B, the 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 B. For example, by mass ratio, a range of 99.9:0.1 to 60:40 is preferred, a range of 99:1 to 70:30 is more preferred, and a range of 95:5 to 80:20 is more preferred. This is because by maintaining the solid resin to liquid resin ratio within the aforementioned range, the shear bond strength of the thermosetting adhesive layer B and the second surface of the adhesive sheet formed by the thermosetting adhesive layer B can be sufficiently lower than the shear bond strength of the first surface.

[0114] The thermosetting adhesive layer B uses a thermosetting resin with a weight-average molecular weight of 100 or more and 20,000 or less. From the viewpoint of reducing the initial adhesion (adhesion) of the thermosetting adhesive layer, it is preferred to prevent misalignment of the adhesive patch or adhesion to a position different from the intended position when the insert member is inserted into the gap of the inserted member, thus obtaining an adhesive patch with high insertability. The weight-average molecular weight of the thermosetting resin is preferably 250 or more and 10,000 or less, more preferably 500 or more and 5,000 or less.

[0115] The total amount of the aforementioned thermosetting resin preferably comprises 30% to 99% by mass of the total resin component of the thermosetting adhesive layer B out of 100% by mass, more preferably 35% to 70% by mass, and even more preferably 40% to 60% by mass. By ensuring that the content of thermosetting resin in the thermosetting adhesive layer B is within the above range, the initial adhesion (bonding strength) of the thermosetting adhesive layer can be appropriately reduced, resulting in an adhesive sheet with higher insertability and easier maintenance of its sheet shape at room temperature, thus improving operability.

[0116] (Expanding agent) The thermosetting adhesive layer B contains one or more expanding agents. Preferably, the expanding agent is one that allows the expanded thermosetting adhesive layer B to form a porous structure within the layer. Details regarding the expanding agent are the same as those described in item (1) Thermosetting adhesive layer A above. It should be noted that the expanding agent and its content in the thermosetting adhesive layer B may be the same as or different from the expanding agent and its content in the thermosetting adhesive layer A.

[0117] The content of the aforementioned expanding agent, preferably the content of the aforementioned thermally expandable capsule, is preferably in the range of 0.3 parts by weight to 30 parts by weight, more preferably in the range of 0.5 parts by weight to 25 parts by weight, and even more preferably in the range of 1 part by weight to 20 parts by weight, relative to 100 parts by weight of the total resin component of the aforementioned thermally expandable thermosetting adhesive layer B. By ensuring that the content of the expanding agent is within the aforementioned range, the gaps in the inserted member can be sufficiently filled, and a high adhesive force can be maintained on the adhered object, i.e., the inserted member or the inserted member, thereby firmly bonding the inserted member and the inserted member together.

[0118] (Curing agent) The thermosetting adhesive layer B preferably contains one or more curing agents capable of reacting with the thermosetting resin. This is because, when the thermosetting adhesive layer B is heated, the thermosetting resin fully cures and exhibits high adhesive strength. The curing agent is preferably contained before the thermosetting adhesive layer B is heat-cured or before it is formed into a sheet-like thermosetting adhesive layer A. Details regarding the curing agent can be the same as those described in item (1) Thermosetting adhesive layer A above. It should be noted that the curing agent contained in the thermosetting adhesive layer B may be the same as or different from the curing agent contained in the thermosetting adhesive layer A.

[0119] The curing agent is preferably used in the range of 0.1 parts to 60 parts by weight relative to the total 100 parts by weight of the thermosetting resin contained in the thermally expandable thermosetting adhesive layer B. It is more preferably used in the range of 0.5 parts to 45 parts by weight. Since the thermosetting resin can be fully cured, it is more preferably used in the range of 1 part to 30 parts by weight.

[0120] (Curing accelerator) Thermosetting adhesive layer B may also contain a curing accelerator. Details regarding the curing accelerator are the same as those described in item (1) Thermosetting adhesive layer A above. It should be noted that the curing accelerator contained in thermosetting adhesive layer B may be the same as or different from the curing accelerator contained in thermosetting adhesive layer A.

[0121] (Thermoplastic resin) Even when used in environments with large temperature variations after expansion, the thermoplastic adhesive layer B can contain thermoplastic resin within a range that does not impair the fixation of the joint. Details and content of the thermoplastic resin are the same as those described in item (1) Thermoplastic adhesive layer A above. It should be noted that the thermoplastic resin contained in thermoplastic adhesive layer B may be the same as or different from the thermoplastic resin contained in thermoplastic adhesive layer A.

[0122] (Any other ingredients) In addition to the above-mentioned components, the thermally expandable thermosetting adhesive layer B 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.

[0123] (3) Arbitrary composition The adhesive sheet of the present invention has at least thermally expandable thermosetting adhesive layers A and B, but may have any configuration as needed. The adhesive sheet of the present invention may be as described above. Figure 1 As illustrated, the thermosetting adhesive layer B can also be directly laminated onto one side of the thermosetting adhesive layer A, as shown in the example. Figure 2 As illustrated, there is an intermediate layer between thermally expandable thermosetting adhesive layer A and thermally expandable thermosetting adhesive layer B, with a first side of the intermediate layer in contact with thermally expandable thermosetting adhesive layer A and a second side of the intermediate layer in contact with thermally expandable thermosetting adhesive layer B.

[0124] The intermediate layer is preferably a heat-resistant substrate. The level of heat resistance varies depending on the application, and the melting point is preferably 150°C or higher, more preferably 200°C or higher, and even more preferably 250°C or higher.

[0125] It should be noted that the melting point mentioned above refers to the temperature representing the maximum endothermic peak, which was determined by using a differential scanning calorimeter (DSC) to heat the above-mentioned substrate from 30°C at a heating rate of 10°C / min.

[0126] Specifically, examples of heat-resistant substrates include polybutylene terephthalate, polyethylene naphthalate (PEN), polyamides, polyimides, polyetherimides, polysulfones, polyetherketones (PEEK), polyphenylene sulfide (PPS), and modified polyphenylene ethers.

[0127] The intermediate layer preferably has 1 μ m or more and 200 μ A thickness of less than m, preferably having 2 μ m or more and 150 μ Thickness below m, further preferably having 3 m μ m or more and 100 μ The thickness is less than m. This is because, by setting the thickness of the intermediate layer to the above range, when the A-side of the thermosetting adhesive layer of the adhesive sheet of the present invention is attached to an insert member, a component to be inserted, or other adhered object, even if the surface of the adhered object is rough or uneven, it can fully follow the surface shape of the adhered object and obtain excellent adhesion. The intermediate layer can be composed of a single layer of substrate having the above-mentioned heat resistance, or it can be composed of two or more layers of substrate having the same or different heat resistance.

[0128] The adhesive sheet of the present invention may have a release liner on the side of the thermosetting adhesive layer A opposite to the side of the thermosetting adhesive layer B. Similarly, the adhesive sheet of the present invention may also have a release liner on the side of the thermosetting adhesive layer B opposite to the side of the thermosetting adhesive layer A. The release liner can be made of known materials such as resin films.

[0129] (4) Other The total thickness of the adhesive sheet of the present invention before heating (before expansion) is preferably 10. μ m or more and 600 μ m or less, preferably 50 m μ m or more and 500 μ Below m, more preferably 100 μ m or more and 400 μ The thickness should be less than m. Furthermore, the total thickness after heating (expansion) is preferably 20 mm. μ m or more and 2500 μ m or less, preferably 40 m μ m or more and 2000 μ Below m, more preferably 100 μ m or more and 1000 μ Below m. It should be noted that the total thickness of the adhesive sheet does not include the thickness of the release liner.

[0130] The shear bond strength of the adhesive sheet of the present invention after expansion (heating) is preferably 3 MPa or more, more preferably 6 MPa or more, and even more preferably 9 MPa or more at room temperature (23°C). This is because it exhibits excellent adhesion retention performance to the insert member and the inserted member. Furthermore, the shear bond strength after expansion (heating) at 150°C is preferably 1 MPa or more, more preferably 4 MPa or more, and even more preferably 7 MPa or more. This is because it exhibits excellent adhesion retention performance to the insert member and the inserted member even at high temperatures, and can achieve higher retention performance. It should be noted that the higher the shear bond strength at both room temperature and 150°C after expansion (heating), the better, but there is no particular limitation; for example, it can be set to 15 MPa or less. The shear bond strength of the adhesive sheet of the present invention after expansion (heating) is measured by the method described in the embodiments below.

[0131] The adhesive sheet of the present invention can be manufactured, for example, by the following steps: applying a thermosetting adhesive composition a to a release liner and drying it to form a thermosetting adhesive layer A; applying a thermosetting adhesive composition b to another release liner and drying it to form a thermosetting adhesive layer B; transferring the thermosetting adhesive layer A onto one side of the thermosetting adhesive layer B and pressing them together.

[0132] Furthermore, if the adhesive sheet of the present invention has an intermediate layer, it can be manufactured, for example, by the following steps: applying a thermosetting adhesive composition a to a release liner and drying it to form a thermosetting adhesive layer A; applying a thermosetting adhesive composition b to another release liner and drying it to form a thermosetting adhesive layer B; bonding the intermediate layer to the thermosetting adhesive layer A; and bonding the thermosetting adhesive layer B to the side of the intermediate layer opposite to the side of the thermosetting adhesive layer A.

[0133] The adhesive sheet of the present invention is useful in applications where it is used between two components to fill the gap between them and bond the components together. Specifically, the adhesive sheet of the present invention expands and cures thermally expandable thermosetting adhesive layers A and B by heating, thus fully filling the gap. Furthermore, even after expansion at high temperatures, thermally expandable thermosetting adhesive layers A and B can maintain high adhesive strength. Therefore, it is particularly useful for filling and bonding components exposed to high temperatures, such as magnets and motor core components in motors of hybrid vehicles.

[0134] Furthermore, the adhesive sheet of the present invention is not limited to the application of bonding an insert member to an inserted member, and can be used in 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 within the gap are bonded by the adhesive sheet.

[0135] II. Items One aspect of the article of the present invention includes a first adhesive and a second adhesive, the second adhesive having a gap, the first adhesive being disposed within the gap of the second adhesive, and an expansion of the adhesive sheet described in the section "I. Adhesive Sheet" being disposed between the first adhesive and the second adhesive within the gap, one of the first adhesive and the second adhesive being bonded to the expansion of the thermosetting adhesive layer A, and the other being bonded to the expansion of the thermosetting adhesive layer B.

[0136] According to this method, the gap between the first and second adhered objects is filled with the expansion (cured product) of the thermosetting adhesive layers A and B described in the "I. Adhesive Sheet" section above. The first and second adhered objects are bonded through the expansion (cured product) of the thermosetting adhesive layers A and B above, so that high bonding strength can be maintained even in high temperature environments and high heat resistance can be achieved.

[0137] In this type of article, from the viewpoint that the article can be easily manufactured by inserting the adhesive sheet into the gap of the second adhesive sheet while the adhesive sheet is attached to the first adhesive sheet, regardless of the width or size of the gap, it is preferable that the first adhesive sheet is bonded to the expanded material of the thermosetting adhesive layer A, and the second adhesive sheet is bonded to the expanded material of the thermosetting adhesive layer B.

[0138] In addition, 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 expansions of the adhesive sheet described in item "I. Adhesive Sheet" being disposed within the gap, between the first adhesive and the third adhesive, and between the first adhesive and the fourth adhesive, respectively. At least one of the first adhesive, the third adhesive, and the fourth adhesive is bonded to the expansion of the thermosetting adhesive layer A, and the other is bonded to the expansion of the thermosetting adhesive layer B.

[0139] According to this method, in the gap between the third and fourth adhered objects, the expansion material of the thermosetting adhesive layers A and B described in the "I. Adhesive Sheet" section is filled between the first and third adhered objects and between the first and fourth adhered objects, respectively. The first and third adhered objects, as well as the first and fourth adhered objects, are bonded through the expansion material of the thermosetting adhesive layers A and B, respectively, thus maintaining high bonding strength even in high-temperature environments.

[0140] In this type of article, from the viewpoint of ease of manufacture, by inserting the adhesive sheet into the gap while it is attached to the first adhesive object, the article can be easily manufactured regardless of the width or size of the gap. It is preferable that the first adhesive object is bonded to the expanded material of the thermosetting adhesive layer A, and the third and fourth adhesive objects are bonded to the expanded material of the thermosetting adhesive layer B.

[0141] As the article of the present invention can be appropriately selected from various types of objects to be adhered, there are no particular limitations. For example, motors used in automobiles, civilian equipment, robots, etc. can be cited.

[0142] The articles of the present invention can be manufactured, for example, by the article manufacturing method described later.

[0143] 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".

[0144] As one method of manufacturing the article of the present invention, the method comprises the following steps: step [1A], attaching the first surface of the adhesive sheet described in item "I. Adhesive sheet" to the surface of the first adherend or the surface of the gap formed in the second adherend; step [2A], inserting the first adherend into the gap; and step [3A], heating the adhesive sheet to expand and cure the thermally expandable thermosetting adhesive layer A and the thermally expandable thermosetting adhesive layer B, thereby bonding the first adherend and the second adherend through the expansion of the adhesive sheet.

[0145] like Figure 3 As illustrated, firstly, the first surface of the adhesive sheet 10 described in the "I. Adhesive Sheet" section above, namely the thermally expanding thermosetting adhesive layer A of the adhesive sheet 10, is attached to both sides of the first adherend 11. Figure 3 (a) reference numeral 1) Figure 3(a), process [1A]). Next, the first adhesive 11, to which the adhesive piece 10 is attached, is inserted into the gap S formed in the second adhesive 12. Figure 3 (b), process [2A]). Next, the adhesive sheet 10 is heated to heat the thermally expandable thermosetting adhesive layer A and the thermally expandable thermosetting adhesive layer B. Figure 3 (c) Reference numerals 1 and 2) indicate expansion and curing. At this time, the expansion 1' of the aforementioned thermosetting adhesive layer A and the expansion 2' of the aforementioned thermosetting adhesive layer B fill the void S. The second surface of the expanded adhesive sheet 10', i.e., the surface of the expansion 2' of the aforementioned thermosetting adhesive layer B, contacts and adheres to the void surface of the second adhered object 12. Thus, an article 20 is obtained by bonding the first adhered object 11 and the second adhered object 12 together with the expansion 10' of the adhesive sheet. Figure 3 (c), Process [3A]).

[0146] As another method of manufacturing the article of the present invention, it includes the following steps: step [1B], attaching the first surface of the adhesive sheet described in item "I. Adhesive sheet" to the surface of the first adhesive or the surface of the gap formed by the third adhesive and the fourth adhesive; step [2B], inserting the first adhesive into the gap; and step [3B], heating the adhesive sheet to expand and cure the thermally expandable thermosetting adhesive layer A and the thermally expandable thermosetting adhesive layer B, and bonding the first adhesive, the third adhesive, and the fourth adhesive through the expanded material of the adhesive sheet.

[0147] like Figure 4 As illustrated, the first surface of the adhesive sheet 10 described in the "I. Adhesive Sheet" section above, namely the thermally expandable thermosetting adhesive layer A, is first attached to both surfaces of the first adherend 11. Figure 4 (a) The face of reference numeral 1) in the attached figure ( Figure 4 (a), step [1B]). Next, the first adhesive 11, to which the adhesive piece 10 is attached, is inserted into the gap S formed by the third adhesive 13 and the fourth adhesive 14. Figure 4 (b), process [2B]). Next, the adhesive sheet 10 is heated to heat the thermally expandable thermosetting adhesive layer A and the thermally expandable thermosetting adhesive layer B. Figure 4 (c) Reference numerals 1 and 2) indicate expansion and curing. At this time, the expanded material ( ) of the aforementioned thermally expandable thermosetting adhesive layer A... Figure 4 (c) reference numeral 1') and the expansion of the above-mentioned thermally expandable thermosetting adhesive layer B ( Figure 4(c) The reference numeral 2' in the attached figure fills the gap S. The second surface of the expanded adhesive piece 10', i.e., the surface of the expanded material 2' of the thermally expandable adhesive layer B, contacts and adheres to the surface constituting the gap of the third adhered object 13 and the surface constituting the gap of the fourth adhered object 14. Thus, an article 20 is obtained by bonding one side of the first adhered object 11 to the third adhered object 13, the other side of the first adhered object 11 to the fourth adhered object 14, respectively. Figure 3 (c), process [3B]).

[0148] According to the method for manufacturing an article of the present invention, when inserting an inserting member, i.e., a first adhesive, into a gap formed by an inserting member, i.e., a second adhesive, or a gap formed by a third adhesive and a fourth adhesive, by attaching the first surface of the adhesive sheet to the desired adhesive, it is possible to prevent the adhesive sheet from shifting its adhesive position during insertion. Since the second surface of the adhesive sheet is exposed, it is possible to prevent insertion obstruction caused by the adhesiveness of the adhesive sheet surface and to prevent positional shift of the adhesive sheet due to adhesion to other adhesives. Furthermore, the heated adhesive sheet can maintain high adhesive strength even at high temperatures, thus enabling the manufacture of components with high heat resistance.

[0149] The first adhered object is equivalent to an inserting member. Furthermore, the second adhered object with a gap, and the third and fourth adhered objects forming the gap, are equivalent to inserted members. The gap in the second adhered object can be, for example, a hole, groove, or opening formed in the adhered object. Furthermore, the gap between the third and fourth adhered objects can be, for example, a separation space in a separately configured state, or a hole, groove, or opening formed by the third and fourth adhered objects.

[0150] In processes [1A] and [1B], the first surface of the adhesive sheet (the surface of the thermosetting adhesive layer A side) is adhered to the surface of one of the adhered objects that becomes the insert member or the inserted member. It should be noted that in... Figure 3 and Figure 4 In process [1A] and [1B], the first side of the adhesive sheet is attached to both sides (opposite sides) of the first object to be bonded. However, the first side of the adhesive sheet can also be attached to at least one side of the first object to be bonded, or the first side of the adhesive sheet can be attached to three or more sides.

[0151] Alternatively, in steps [1A] and [1B], the first surface of the adhesive sheet can be adhered to the first substrate. In step [1A], the first surface of the adhesive sheet can also be adhered to the surface of the gap formed in the second substrate. On the other hand, in step [1B], it can also be adhered to the surface of the gap formed by the third and fourth substrates. In this case, the first surface of the adhesive sheet can be adhered to one surface of the gap, or it can be adhered to two or more surfaces.

[0152] When the first side of an adhesive sheet is attached to two or more surfaces of an object to be bonded, a single adhesive sheet can be continuously attached to multiple surfaces of the object to be bonded, or an adhesive sheet can be attached to each surface of the object to be bonded. For example, when attaching an adhesive sheet to a first object to be bonded, the first sides of different adhesive sheets can be attached to opposite sides of the first object to hold the first object to be bonded, or a single adhesive sheet can be used to cover multiple surfaces of the first object to be bonded. Similarly, when attaching an adhesive sheet to the surface of a gap formed in a second object to be bonded, or a gap formed by a third object to be bonded and a fourth object to be bonded (the surface of the object to be bonded), the first sides of different adhesive sheets can be attached to opposite sides of the surface of the gap to be bonded, or a single adhesive sheet can be used to cover multiple surfaces of the gap to be bonded.

[0153] There are no particular limitations on the conditions under which the first side (the side of the thermosetting adhesive layer A) of the adhesive sheet is bonded to the surface of the adherend. 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 adhesion of the thermosetting adhesive layer A. Furthermore, it is preferable from the viewpoint that the initial adhesion of the thermosetting adhesive layer B can be maintained.

[0154] In step [2A], the first adhesive is inserted into the gap formed in the second adhesive. Additionally, in step [2B], the first adhesive is inserted into the gap between the third and fourth adhesives. In steps [2A] and [2B], the second surface (the surface of the thermosetting adhesive layer B side) of the adhesive sheet adhered to the adhesive is the outermost surface. Therefore, when the adhesive sheet is adhered to the first adhesive, it can be inserted without adhering to the gap surface. Even if it does adhere, the adhesive sheet is not easily peeled off by the force applied during insertion, thus maintaining temporary fixation and improving insertion performance. Similarly, when the adhesive sheet is adhered to the gap surface, it can be inserted without adhering to the first adhesive. Even if it does adhere, the adhesive sheet is not easily peeled off by the force applied during insertion, thus maintaining temporary fixation and improving insertion performance.

[0155] In processes [3A] and [3B], with the first adherend inserted into the gap, the adhesive sheet is heated to cause the thermosetting adhesive layer A and the thermosetting adhesive layer B to expand and cure. Heating can be performed directly on the thermosetting adhesive layer A and the thermosetting adhesive layer B of the adhesive sheet, or on the entire assembly including the adherend. The heating method can be non-contact or contact, and can include hot air heating, heating in contact with an electric heater, heating by light irradiation such as infrared heaters or halogen heaters, dielectric heating, induction heating, etc.

[0156] The heating temperatures in steps [3A] and [3B] can be set to temperatures at which the thermosetting adhesive layer A and the thermosetting adhesive layer B can expand and cure. Preferably, these temperatures correspond to the curing temperatures of the thermosetting adhesive layers A and B and the expansion temperature (expansion start temperature) of the expanding agent, and are preferably above the expansion temperature of the expanding agent. Specifically, these temperatures are preferably 80°C to 350°C, more preferably 100°C to 250°C, and even more preferably 150°C to 200°C.

[0157] Furthermore, the heating time in processes [3A] and [3B] can be set to the time during which the thermosetting adhesive layer A and the thermosetting adhesive layer B can expand and cure, preferably at least the expansion time. 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.

[0158] In processes [3A] and [3B], the gap is filled by heating the adhesive sheet to expand. In process [3A], the first and second objects are bonded together through the expanded adhesive sheet. In process [3B], the first object is bonded to the third and fourth objects.

[0159] Within the gap, the adhesive sheet expands upon heating, allowing the expanded material of the thermosetting adhesive layer B to contact the substrate without the adhesive sheet. At this time, the expanded materials of both thermosetting adhesive layers A and B exhibit adhesive force through heating and curing, thus enabling a strong bond between the insert member (first substrate) and the inserted member (second substrate), or the third and fourth substrates. Furthermore, the expanded materials of thermosetting adhesive layers A and B are cured products with high heat resistance, thus maintaining high adhesive force even at high temperatures.

[0160] The article obtained by the manufacturing method of the present invention is not particularly limited, and examples include motors mounted in hybrid vehicles. Specifically, the motor can be manufactured by pre-bonding a thermosetting adhesive layer A of an adhesive sheet to a part such as a magnet, inserting the part with the adhesive sheet attached into and placing it in the gap of the core member constituting the motor, and then heating the thermosetting adhesive layers A and B to expand them. Therefore, the manufacturing method of the article of the present invention is useful as a method for manufacturing motors.

[0161] 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. All such technical solutions are included within the technical scope of this disclosure.

[0162] Example The present invention will be specifically illustrated below through examples.

[0163] (Preparation Example 1) <Preparation of a thermosetting adhesive composition with thermal expansion properties (a-1)> A thermosetting resin composition (a-1) was prepared by combining 40 parts by weight of epoxy resin 1 (BPA type, epoxy equivalent 8000 g / eq., solid (25℃), softening point above 200℃), 35 parts by weight of epoxy resin 2 (BPA type, epoxy equivalent 188 g / eq., 11,000 mPa·s (25℃)), and 25 parts by weight of epoxy resin 3 (dicyclopentadiene type, epoxy equivalent 280 g / eq., solid (25℃), softening point 100℃). At this point, the total epoxy equivalent of the above thermosetting resin composition (a-1) is 357 g / eq. Next, 4.7 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 expanding capsule, expansion start temperature 125°C, average particle size 13) were added. μ m) was dissolved in 60 parts by mass of methyl ethyl ketone to prepare a solution-like thermally expanding thermosetting adhesive composition (a-1).

[0164] (Preparation Example 2) <Preparation of thermosetting adhesive composition (a-2) with thermal expansion> The amount of epoxy resin 1 was changed from 40 parts by mass to 30 parts by mass, and 30 parts by mass of epoxy resin 4 (modified BPA type, epoxy equivalent 400 g / eq., 1.4 million mPa·s (25°C)) was used instead of epoxy resin 2. 40 parts by mass of epoxy resin 5 (modified phenolic varnish type, epoxy equivalent 160 g / eq., semi-solid (25°C)) was used instead of epoxy resin 3. The amount of curing agent 1 was changed from 4.7 parts by mass to 5.7 parts by mass. Otherwise, a thermosetting resin composition (a-2) and a solution-like thermally expanding thermosetting adhesive composition (a-2) were prepared using the same method as in Preparation Example 1. At this time, the total epoxy equivalent of the above thermosetting resin composition (a-2) was 304 g / eq.

[0165] (Preparation Example 3) <Preparation of Thermally Expandable Thermosetting Adhesive Composition (b-1)> The amount of epoxy resin 1 used was changed from 40 parts by mass to 35 parts by mass, the amount of epoxy resin 2 used was changed from 35 parts by mass to 7 parts by mass, the amount of epoxy resin 3 used was changed from 25 parts by mass to 58 parts by mass, and the amount of curing agent 1 used was changed from 4.7 parts by mass to 4.1 parts by mass. Otherwise, a thermosetting resin composition (b-1) and a solution-like thermally expanding thermosetting adhesive composition (b-1) were prepared using the same method as in Preparation Example 1. At this time, the total epoxy equivalent of the above-mentioned thermosetting resin composition (b-1) was 402 g / eq.

[0166] (Preparation Example 4) <Preparation of Thermally Expandable Thermosetting Adhesive Composition (b-2)> The amount of epoxy resin 1 used was changed from 40 parts by mass to 35 parts by mass, the amount of epoxy resin 2 used was changed from 35 parts by mass to 15 parts by mass, the amount of epoxy resin 3 used was changed from 25 parts by mass to 50 parts by mass, and the amount of curing agent 1 used was changed from 4.7 parts by mass to 4.6 parts by mass. Otherwise, a thermosetting resin composition (b-2) and a solution-like thermally expanding thermosetting adhesive composition (b-2) were prepared using the same method as in Preparation Example 1. At this time, the total epoxy equivalent of the above-mentioned thermosetting resin composition (b-2) was 381 g / eq.

[0167] (Preparation Example 5) <Preparation of Thermally Expandable Thermosetting Adhesive Composition (b-3)> The amount of epoxy resin 1 used was changed from 40 parts by mass to 35 parts by mass, 7 parts by mass of epoxy resin 4 was used instead of epoxy resin 2, 58 parts by mass of epoxy resin 5 was used instead of epoxy resin 3, and the amount of curing agent 1 used was changed from 4.7 parts by mass to 4.4 parts by mass. Otherwise, a thermosetting resin composition (b-3) and a solution-like thermally expanding thermosetting adhesive composition (b-3) were prepared using the same method as in Preparation Example 1. At this time, the total epoxy equivalent of the above thermosetting resin composition (b-3) was 260 g / eq.

[0168] (Preparation Example 6) <Preparation of thermosetting adhesive composition (b'-1)> The amount of expanding agent 1 used was changed from 1 part by mass to 0 parts by mass. Otherwise, a thermosetting resin composition (b'-1) and a solution-like thermosetting adhesive composition (b'-1) were prepared by the same method as in Preparation Example 3. At this time, the total epoxy equivalent of the above-mentioned thermosetting resin composition (b'-1) was 402 g / eq.

[0169] (Example 1) Using a rod-shaped metal applicator, the thermally expandable thermosetting adhesive composition (a-1) obtained in the above-described modified example 1 was applied to a dried thickness of 62. μ Apply the coating to the release liner (thickness 50) using the m method. μ The surface of a polyethylene terephthalate film (one side of which was treated with an organosilicon compound) was then coated. The resulting coating was dried in a dryer at 85°C for 5 minutes to obtain a thickness of 62 μm. μ m is a sheet-like, thermally expandable, thermosetting adhesive layer (A-1).

[0170] The surface of the aforementioned thermosetting adhesive layer (A-1) has an overlap thickness of 25. μ A polyimide film of m is applied at 23°C using a laminator with a linear pressure of 3 N / mm to obtain a laminate with a polyimide film laminated on one side of the above-mentioned thermosetting thermal expansion adhesive layer (A-1).

[0171] Next, using a rod-shaped metal applicator, the thermally expandable thermosetting adhesive composition (b-1) obtained in the above-described modified example 3 was applied to a dried thickness of 62. μ The coating was applied to the surface of the release liner using an m-shaped method. The resulting coating was then dried in an 85°C dryer for 5 minutes, yielding a thickness of 62 mm. μ m is a sheet-like, thermally expandable, thermosetting adhesive layer (B-1).

[0172] The aforementioned thermosetting adhesive layer (B-1) is overlapped with the polyimide film side of a laminate in which a polyimide film is laminated on one side of the aforementioned thermosetting expandable adhesive layer (A-1). The lamination is then performed using a laminator preheated to 50°C with a linear pressure of 3 N / mm, thereby obtaining a thickness of 149 mm. μ The adhesive sheet (X-1) has a thickness m (excluding the thickness of the release liner; the same applies below). The adhesive sheet (X-1) has the side facing the thermosetting adhesive layer (A-1) as its first side and the side facing the thermosetting adhesive layer (B-1) as its second side. The shear bond strength of the first and second sides of the adhesive sheet (X-1), as well as the shear bond strength of the thermosetting adhesive layers (A-1) and (B-1), are the values ​​shown in Table 1 below. Furthermore, after heating at 150°C for 60 minutes, the glass transition temperature of the cured (expanded) thermosetting adhesive layer (A-1) in the adhesive sheet (X-1) is 132°C, and the glass transition temperature of the thermosetting adhesive layer (B-1) is 165°C. It should be noted that the glass transition temperature was determined using the method described in section "I. Adhesive Sheet" above. The same method applies to the following examples and comparative examples.

[0173] It should be noted that the shear bond strength of the first and second surfaces of the adhesive sheet, as well as the shear bond strength of each thermosetting adhesive layer, were determined using the methods described later. The same applies to other embodiments and comparative examples.

[0174] (Example 2) A thermosetting adhesive layer (B-2) was prepared using a thermosetting adhesive composition (b-2) instead of a thermosetting adhesive composition (b-1), and a thermosetting adhesive layer (B-2) was used instead of a thermosetting adhesive layer (B-1). Otherwise, an adhesive sheet (X-2) was obtained using the same method as in Example 1. The adhesive sheet (X-2) had the side of the thermosetting adhesive layer (A-1) as its first side and the side of the thermosetting adhesive layer (B-2) as its second side. The shear bond strength of the first and second sides of the adhesive sheet (X-2), as well as the shear bond strength of the thermosetting adhesive layers (A-1) and (B-2), are the values ​​shown in Table 1 described later. In addition, the glass transition temperature of the thermosetting adhesive layer (A-1) after curing (expanding) in the adhesive sheet (X-2) after heating at 150°C for 60 minutes is 132°C, and the glass transition temperature of the thermosetting adhesive layer (B-2) is 153°C.

[0175] (Example 3) A thermosetting adhesive layer (A-2) is prepared by using a thermosetting adhesive composition (a-2) instead of a thermosetting adhesive composition (a-1), a thermosetting adhesive layer (B-3) is prepared by using a thermosetting adhesive composition (b-3) instead of a thermosetting adhesive composition (b-1), a thermosetting adhesive layer (B-3) is prepared by using a thermosetting adhesive layer (A-2) instead of a thermosetting adhesive layer (A-1), and a thermosetting adhesive layer (B-3) instead of a thermosetting adhesive layer (B-1). Otherwise, an adhesive sheet (X-3) is obtained by the same method as in Example 1. The adhesive sheet (X-3) has the side of the thermosetting adhesive layer (A-2) as its first side and the side of the thermosetting adhesive layer (B-3) as its second side. The shear bond strength of the first and second sides of the adhesive sheet (X-3), as well as the shear bond strength of the thermosetting adhesive layers (A-2) and (B-3), are the values ​​shown in Table 1 below. Furthermore, after heating at 150°C for 60 minutes, the glass transition temperature of the cured (expanded) thermosetting adhesive layer (A-2) in the adhesive sheet (X-3) is 125°C, and the glass transition temperature of the thermosetting adhesive layer (B-3) is 159°C.

[0176] (Example 4) Using a rod-shaped metal applicator, the thermally expandable thermosetting adhesive composition (a-1) obtained in Preparation Example 1 above was applied to a dried thickness of 75. μ Apply the coating to the release liner (thickness 50) using the m method. μ The surface of a polyethylene terephthalate film (one side of which was treated with an organosilicon compound) was then coated. The resulting coating was dried in an 85°C dryer for 5 minutes to obtain a thickness of 75 μm. μ m is a sheet-like, thermally expandable, thermosetting adhesive layer (A-4).

[0177] Next, using a rod-shaped metal applicator, the thermally expandable thermosetting adhesive composition (b-1) obtained in Preparation Example 3 was applied to a dried thickness of 75 mm. μ The coating was applied to the surface of the release liner using an m-shaped method. The resulting coating was then dried in an 85°C dryer for 5 minutes, yielding a thickness of 75 mm. μ m is a sheet-like, thermally expandable, thermosetting adhesive layer (B-4).

[0178] The above-mentioned thermosetting adhesive layer (B-4) is overlapped with the adhesive layer side of the above-mentioned thermosetting expandable adhesive layer (A-4), and then bonded using a laminator preheated to 50°C with a linear pressure of 3 N / mm, thereby obtaining a thickness of 150 mm. μAdhesive sheet (X-4) of m. Adhesive sheet (X-4) has the side facing the thermosetting adhesive layer (A-4) as the first side and the side facing the thermosetting adhesive layer (B-4) as the second side. The shear bond strength of the first and second sides of adhesive sheet (X-4), and the shear bond strength of the thermosetting adhesive layers (A-4) and (B-4) are the values ​​shown in Table 1 below. Furthermore, after heating at 150°C for 60 minutes, the glass transition temperature of the cured (expanded) thermosetting adhesive layer (A-4) in adhesive sheet (X-4) is 132°C, and the glass transition temperature of the thermosetting adhesive layer (B-4) is 165°C.

[0179] (Comparative Example 1) The adhesive sheet (X'-1) is obtained by using a thermosetting adhesive layer (A-1) instead of a thermosetting adhesive layer (B-1), except that the same method as in Example 1 is employed. The adhesive sheet (X'-1) has one side of an arbitrarily selected thermosetting adhesive layer (A-1) as its first side and the other side of the thermosetting adhesive layer (A-1) as its second side. The shear bond strength of the first and second sides of the adhesive sheet (X'-1), as well as the shear bond strength of the thermosetting adhesive layer (A-1), are the values ​​shown in Table 1 described later. Furthermore, the glass transition temperature of the thermosetting adhesive layer (A-1) after curing (expanding) in the adhesive sheet (X'-1) after heating at 150°C for 60 minutes is the same as that of the thermosetting adhesive layer (A-1) after curing (expanding) in the adhesive sheet (X-1) of Example 1.

[0180] (Comparative Example 2) The adhesive sheet (X'-2) was obtained by using a thermosetting adhesive layer (B-1) instead of a thermosetting adhesive layer (A-1), except that the method was the same as in Example 1. The adhesive sheet (X'-2) had one side of an arbitrarily selected thermosetting adhesive layer (B-1) as its first side and the other side of the thermosetting adhesive layer (B-1) as its second side. The shear bond strength of the first and second sides of the adhesive sheet (X'-2), and the shear bond strength of the thermosetting adhesive layer (B-1), are the values ​​shown in Table 1 described later. Furthermore, the glass transition temperature of the thermosetting adhesive layer (B-1) after curing (expanding) in the adhesive sheet (X'-2) after heating at 150°C for 60 minutes is the same as that of the thermosetting adhesive layer (B-1) after curing (expanding) in the adhesive sheet (X-1) of Example 1.

[0181] (Comparative Example 3) A thermosetting adhesive layer (B'-1) was prepared using a thermosetting adhesive composition (b'-1) instead of a thermo-expanding thermosetting adhesive composition (b-1), and a thermosetting adhesive layer (B'-1) was used instead of a thermo-expanding thermosetting adhesive layer (B-1). Otherwise, an adhesive sheet (X'-3) was obtained using the same method as in Example 1. The adhesive sheet (X'-3) had the side facing the thermo-expanding thermosetting adhesive layer (A-1) as its first side and the side facing the thermosetting adhesive layer (B'-1) as its second side. The shear bond strength of the first and second sides of the adhesive sheet (X'-3), as well as the shear bond strength of the thermo-expanding thermosetting adhesive layers (A-1) and (B'-1), are the values ​​shown in Table 1 described later. Furthermore, the glass transition temperature of the cured (expanded) thermosetting adhesive layer (A-1) in the adhesive sheet (X'-2) after heating at 150°C for 60 minutes is the same as that of the cured (expanded) thermosetting adhesive layer (A-1) in the adhesive sheet (X-1) of Example 1, and the glass transition temperature of the cured (expanded) thermosetting adhesive layer (B'-1) is 165°C.

[0182] [Evaluation 1: Determination of Expansion Rate] The thermosetting adhesive layers (A-1) to (A-2) and (B-1) to (B-3), as well as the thermosetting adhesive layer (B'-1), on the release liner used in the fabrication of the adhesive sheets of the above embodiments and comparative examples were used as test samples. The thickness of the thermosetting adhesive layer or thermosetting adhesive layer of the test samples before heating was measured using a thickness gauge. Next, the test samples were heated at 150°C for 60 minutes, and the thickness of the thermosetting adhesive layer or thermosetting adhesive layer after heating was measured using a thickness gauge. The expansion rate was calculated according to the following mathematical formula.

[0183] Expansion rate [%] = Thickness of the thermosetting adhesive layer after heating [ ] μ m] / Thickness of the thermosetting adhesive layer before heating [ ] μ m]×100[% [Evaluation 2: Determination of shear bond strength before heating] (Evaluation 2-1: Determination of shear bond strength of thermosetting adhesive layer with thermal expansion before heating) The thermosetting adhesive layers (A-1) to (A-2) and (B-1) to (B-3) on the release liner used in the production of the adhesive sheets of the above embodiments and comparative examples, as well as the thermosetting adhesive layer (B'-1), were cut into 10mm × 10mm sizes to obtain samples as test samples. Two smooth aluminum plates with a width of 15mm × length of 70mm × thickness of 0.5mm were degreased, and the test sample was pressed onto the upper surface of one aluminum plate using a 2kg hand roller at 23°C.

[0184] Next, the release liner of the test sample pressed onto 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 5 minutes, the ends of the two aluminum plates were clamped, and the adhesive force in the shear direction of the thermosetting adhesive layer was measured using a Tensilon tensile testing machine [manufactured by A&D Corporation, model: RTM-100] at a tensile test of 10 mm / min in a 180-degree direction.

[0185] (Evaluation 2-2: Determination of the shear bond strength of the first and second surfaces of the bonded sheet before heating) Test samples were obtained by cutting the adhesive sheets of the above embodiments and comparative examples into 10mm × 10mm pieces. Two smooth aluminum plates with a width of 15mm × length of 70mm × thickness of 0.5mm were degreased. A strong adhesive for fixing the test sample (a two-component mixed room-temperature curing acrylic adhesive, Metal Lock manufactured by Cemedine) was applied to the upper surface of one aluminum plate. The release liner on the second side (the second side of the adhesive sheet) of the test sample was peeled off. The second side of the test sample was then overlapped onto the aluminum plate through the strong adhesive, and the sample was pressed at 23°C using a 2kg hand roller. Next, the release liner on the first side of the test sample pressed onto the aluminum plate was peeled off, and another aluminum plate with a degreased smooth surface was overlapped on the upper surface (the second side of the adhesive sheet) 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 during a tensile test at 10 mm / min in a 180-degree direction. This shear force is taken as the shear bond strength of the first surface of the bonded sheet.

[0186] In addition, the first side (the first side of the adhesive sheet) 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 side (the second side of the adhesive sheet) of the test sample. Otherwise, the same measurement method as described above was performed, and the adhesive force in the shear direction was measured. This adhesive force was then taken as the shear bond strength of the second side of the adhesive sheet.

[0187] [Evaluation 3: Evaluation of the temporary fixation of the components] The adhesive sheets obtained in the above embodiments and comparative examples were cut into test pieces of 15mm × 15mm size as test samples. Next, for the above test samples, the release liner on one side of the adhesive sheet was peeled off and overlapped in the center of a degreased and smooth SUS plate with a width of 40mm × length of 50mm × thickness of 3mm. The test samples were then pressed at 23°C for 10 seconds with a load of 0.5MPa to fix the test samples.

[0188] 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 dropped vertically. This operation was repeated 10 times. Then, the offset caused by the drop of the test sample was measured, and the temporary fixation of the component was evaluated according to the following criteria.

[0189] (Judgment Criteria) ◎: The offset of the test sample is 0 mm.

[0190] 〇: The offset of the test sample is less than 1mm.

[0191] △: The offset of the test sample is greater than 1 mm.

[0192] ×: The test sample was peeled off from the SUS plate.

[0193] [Evaluation 4: Evaluation method for the insertability of components] The adhesive sheets obtained in the above embodiments and comparative examples were cut to a size of 15mm × 15mm. Next, the release liner on one side of the adhesive sheet was peeled off and overlapped onto the center of one side of a degreased, smooth SUS board (30mm wide × 30mm long × 1mm thick). The adhesive sheet was then pressed at 23°C for 10 seconds under a load of 0.5MPa to fix it in place. The sample obtained after removing the release liner from both sides of the adhesive sheet fixed to the SUS board was then used as a test sample.

[0194] 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.

[0195] 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.

[0196] (Judgment Criteria) ◎: The test sample had its spacer thickness increased by 50% relative to the total thickness of the adhesive sheet and SUS plate. μ It can also pass when m.

[0197] 〇: The test sample increased the thickness of the spacer relative to the total thickness of the adhesive sheet and SUS plate by 50%. μ It cannot pass through at m, and it is thickened to 75. μ It can pass when m.

[0198] △: The test sample increased the thickness of the spacer relative to the total thickness of the adhesive sheet and SUS plate by 75%. μ It cannot pass through at m, and it is thickened by 100. μ It can pass when m.

[0199] ×: The test sample increased the thickness of the spacer relative to the total thickness of the adhesive sheet and SUS plate by 100%. μ It cannot pass even at time m.

[0200] [Evaluation 5: 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 5 As shown, at the end of the upper surface of an aluminum plate 51, two spacers 53, spaced 12 mm apart, are arranged in parallel and bonded together with a width of 5 mm. The total thickness of the adhesive tape used to bond the spacers 53 is 150 mm thicker than the total thickness of the adhesive sheet. μ The component is prepared in the manner of m. Next, on the upper surface side of the aluminum plate 51 and in the gap S between the two spacers 53, the adhesive sheet 10 obtained in the above embodiment and comparative example, which is pre-cut to a size of 10mm×10mm, is peeled off the release liner on the first side of the adhesive sheet 10 and pasted, and is pressed using a 2kg hand roller.

[0201] Next, the release liner on both sides of the adhesive sheet 10 is peeled off, and another aluminum plate 52 (15mm wide × 70mm long × 0.5mm thick) with a smooth, degreased surface is placed on the upper surface (second side) of the adhesive sheet, and they are fixed with clamps. The fixed sheet is heated at 150°C for 60 minutes and then cooled at 23°C for 30 minutes. Next, the sample with the clamps removed is used as the test sample. The ends of the two aluminum plates 51 and 52 are clamped respectively, and the shear force is measured in the 180-degree direction at 10mm / min using a Tensilon tensile testing machine [manufactured by A&D Corporation, model: RTM-100] at 23°C and 150°C.

[0202] The evaluation results are shown in the following table.

[0203] [Table 1]

[0204] [Table 2]

[0205] The adhesive sheets of Examples 1-4 exhibit good temporary fixation and insertion properties for components, and after thermal expansion, they demonstrate high shear adhesion at both room temperature and high temperature. On the other hand, the adhesive sheet of Comparative Example 1, before heating, has a lower shear adhesion force on the first side than on the second side, thus failing to achieve insertion properties. Furthermore, the adhesive sheet of Comparative Example 2 has the same shear adhesion force on both the first and second sides before heating, failing to achieve temporary fixation. The adhesive sheet of Comparative Example 3, after thermal expansion, exhibits worse shear adhesion at both room temperature and high temperature than the adhesive sheets of the Examples, particularly failing to achieve shear adhesion at high temperature. This is presumably because the thermosetting adhesive layer (B'-1) of the adhesive sheet of Comparative Example 3 does not expand upon heating, thus failing to adequately fill the gap between the two adhered objects and failing to achieve sufficient adhesion to the other adhered object. Additionally, the adhesive sheet of Comparative Example 3 only expands the thermally expanding thermosetting adhesive layer (A-1) for adhesion, resulting in insufficient adhesion. Figure 5 Within the limited space shown, it is speculated that the expansion rate of the thermosetting adhesive layer (A-1) in Comparative Example 3 is greater than that of the others. Therefore, after the adhesive sheet of Comparative Example 3 is heated (after expansion), the density of the thermosetting adhesive layer (A-1) becomes sparse, and as a result, it is speculated that it cannot exhibit and maintain sufficient adhesive strength after heating. Attached Figure Description 1…Thermosetting adhesive layer A with thermal expansion properties 1'...The expanded thermosetting adhesive layer A (the expanded material of thermosetting adhesive layer A) 2…Thermo-expandable thermosetting adhesive layer B 2'...The expanded thermosetting adhesive layer B (the expanded material of thermosetting adhesive layer B) 3…Intermediate layer 10… Adhesive sheet 10'... Expanded adhesive sheet (expanded adhesive sheet material) 20… items

Claims

1. An adhesive sheet, characterized in that, The adhesive sheet has opposing first and second surfaces. The first surface is composed of a thermosetting adhesive layer A, which comprises a thermosetting resin and an expanding agent. The second surface is composed of a thermosetting adhesive layer B, which contains a thermosetting resin and an expanding agent, and has a different composition from the thermosetting adhesive layer A. The thermosetting adhesive layer B, which is thermally expandable, is laminated directly or in between other layers onto one side of the thermosetting adhesive layer A. The shear bond strength of the first surface is higher than that of the second surface. After heating at 150°C for 60 minutes, the thickness-direction expansion rates of the thermosetting adhesive layer A and the thermosetting adhesive layer B are both greater than 130%. The shear bond strength of the second surface of the adhesive sheet is less than 0.5 MPa.

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

3. The adhesive sheet according to claim 1 or 2, wherein, The thermosetting adhesive layer A contains at least 10% by mass of a thermosetting resin with a viscosity of less than 3 million mPa·sec at 25°C in all of its resin components.

4. The adhesive sheet according to claim 1 or 2, wherein, The thermosetting adhesive layer B contains, in all resin components of the cured adhesive layer B, less than 40% by mass of a thermosetting resin with a viscosity of less than 3 million mPa·sec at 25°C.

5. The adhesive sheet according to claim 1 or 2, wherein, The glass transition temperatures of the thermosetting adhesive layer A and the thermosetting adhesive layer B, after being heated at 150°C for 60 minutes, are both above 80°C.

6. An article characterized in that, The article has a first adhesive and a second adhesive, the second adhesive having a gap. The first adhesive is disposed within the gap of the second adhesive. Within the gap, between the first adherend and the second adherend, an expansion of the adhesive sheet according to any one of claims 1 to 5 is disposed. One of the first and second adherends is bonded to the expanded thermosetting adhesive layer A, and the other is bonded to the expanded thermosetting adhesive layer B.

7. An article characterized in that, The article has a first adhesive, a third adhesive, and a fourth adhesive, with a gap between the third adhesive and the fourth adhesive. The first adhesive is disposed within the gap. Within the gap, between the first adherend and the third adherend, and between the first adherend and the fourth adherend, an expansion of the adhesive sheet according to any one of claims 1 to 5 is respectively disposed. The first adherend, and at least one of the third and fourth adherends are bonded to the expanded thermosetting adhesive layer A, and the other is bonded to the expanded thermosetting adhesive layer B.

8. A method for manufacturing an article, characterized in that, It has the following processes: Step [1A], wherein the surface of the thermally expandable thermosetting adhesive layer A side of the adhesive sheet according to any one of claims 1 to 5 is adhered to the surface of the first adhered object or to the surface of the void formed in the second adhered object; Step [2A], wherein the first adhesive is inserted into the gap; and Step [3A], wherein the adhesive sheet is heated to cause the thermosetting adhesive layer A and the thermosetting adhesive layer B to expand and cure, and the first substrate and the second substrate are bonded together through the expanded material of the adhesive sheet.

9. A method for manufacturing an article, characterized in that, It has the following processes: Step [1B], wherein the surface of the thermally expandable thermosetting adhesive layer A side of the adhesive sheet according to any one of claims 1 to 5 is adhered to the surface of the first adhered object or to the surface of the gap formed by the third adhered object and the fourth adhered object; Step [2B], wherein the first adhesive is inserted into the gap; and Step [3B], wherein the adhesive sheet is heated to cause the thermosetting adhesive layer A and the thermosetting adhesive layer B to expand and cure, 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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